The Philadelphia 76ers react to criticism of their defense like a defiant youngster being scolded for eating too many cookies.

The more they are lectured, the more outlandish their defense becomes, even though they realize their chances of winning this year's NBA championship hinge almost entirely on how well they play when the other fellow has the ball.

Their attitude drives Coach Billy Cunningham right up a backboard. "We'll work until we get it right," he stormed frequently late in the season. So the 76ers promptly lost six of their final eight games (among their conquerers (New Orleans, Indiana, Houston) and didn't hold an opponent under 100 points the last monoh of the schedule.

"We can't throw a magic switch and play well when we are behind," said 76er guard Doug Collins. "We can't play shootout. We have to force a team to miss, rebound and run. And you can't run taking the ball out of the net."

None of this has been lost on those wonderful run-and-gun artists who play in San Antonio Spurs uniforms. They'd just love to get into a New West showdown, with the 76ers in the final of the Eastern Conference playoffs. Even Philly would have a tough time keeping up with the Spurs in such a wide-open affair.

San Antonio hardly will win any ribbons for its defense, but the Spurs aren't quite as weak in this area as they were laast year. But in fashioning a 52-30 record, third-best in the NBA. Coach Doug Moe didn't go into many games thinking his club will win by turning into a bunch of Bill Russells, Walt Fraziers and John Havliceks.

The Spurs' strength is scoring and everyone - from George (Mr. Cool) Gervin to rejuvenated guard James Silas - can put it in without blinking an eye. They are loose and free, one of the major surprises of the season, and they are rubbing their hands, waiting for a shot at Philly.

First, however, San Antonio faces what could be a dangerous path to the Eastern final. If the Bullets get by Atlanta in this week's first-round best-of-three miniseries, the Spurs and Washington will hook up in a best-of-seven round that both clubs feel they can win.

Washington has the talent and experience to be a dangerous playoff team, although it limped through the last two weeks of the schedule with inconsistent performances, poor defense and injuries to everyone but the ball boy. The Spurs and Bullets split their four games this season, each winning in their home court. And San Antonio would have the home-court advantage in the series.

Philadelphia shouldn't have many problems with either Cleveland or New York in the other semifinal. The Knicks don't play much defense and can't keep up with the 76ers' firepower. The Cavs' slow-down approach can be pesky but Cunningham's depth - he can bring the likes of Lloyd Free, Darryl Dawkins and Steve Mix off the bench - should eventually wear down Cleveland.

The pressure will be Cunningham no matter what opponent he meets in the playoffs. He replaced Gene Shue five games into the season for one reason: to win an NBA title. Although the club appears happier with his casual, friendly approach than with Shue's more distant philosophy, the players remain just as unpredictable.

For example, they had a chance to catch Portland for the NBA's best record the last month of the season and Cunningham felt sure they would begin playing well. Instead, they sat back and asked Julius Erving to carry them. He couldn't and they wound up winning only three more games than San Antonio.

Washington (44-38) vs. Atlanta (41-41)

Hubie Brown probably will be NBA coach of the year for what he has done with the Hawks, the NBA's lowrent club that was supposed to be the league's version of the Oakland A's.

Instead, the Hawks got off to a quick start and refused to fold, thanks to Brown's constant prodding, screaming, pleading and, sometimes, begging. Atlanta has the lowest payroll in the league, with only John Drew and Tom McMillen getting more than $100,000 a year, but Brown had them in contention for fourth place in the Eastern Conference until this past weekend.

"Atlanta feels they can beat us; they want us," said Bullet Coach Dick Motta, whose club won three of four against the Hawks this season. "They really play hard. They've had playoff intensity since Christmas. They fight, they hack, they scratch. It's not pretty but it's effective."

Atlanta relies on Drew, the toss-it-up, what's-defense? forward, for its pressure points. Rookie guard Eddie Johnson finished strongly and midget Charlie Criss is a streak shooter off the bench, but the Hawks depend more on depth (nine players averaged from six to 12 points) than individuals to support Drew offensively.

Their zone defenses give the Bullets fits, the major reason of Washington's three victories over Atlanta exceeded a seven-point margin. The bullets' key towinning probably will be foul shooting. Atlanta, which led the NBA in fouls committed, sent the Bullets to the foul line 167 times in four games; the one contest they lost, they made only 53 percent of 38 tries.

Foul shooting, however, happens to be a major Washington problem. The Bullets were last in the NBA in that category, although they did show signs of improvement at times near the end season.

"Other than Drew, it doesn't matter who they have in foul trouble," said Motta. "If one guy goes out, another guy with about the same ablility comes in the same philosophy built the Great Wall of China. They can afford to be aggressive."

The Hawlks will do a lot of sagging and double-teaming and they will contest almost every pass the Bullets toss. With Washington trying to shake off problems that brought about losses in five of its last nine games, such tactics could prove disruptive.

The Bullets' major goal through the final weeks of the season, besides finishing third, was to get everyone in reasonable health for the playoffs. Although Larry Wright's wrist still bothers him and Tom Henderson's ankles aren't 100 percent, the team is in better shape now than it has been since January, before the injury crunch began.

Bob Dandridge, who has been slowed by a variety of ailments, has the key matchup, against Drew. If Dandridge can keep Drew under control and score some points himself, the Hawks will be vulnerable.

Cleveland (43-39) vs. New York (43-39)

While Walt Frazier sat home nursing a sore foot, the Cavaliers won nine of their last 10 games to burst into the playoffs and make Clyde's future in Cleveland shaky at best.

Coach Bill Fitch, eho made it plain he thought Frazier was not pushing himself hard enough, finally settled on a lineup that saw Foots Walker become the playmaker, Austin Carr the outside shooter, Elmore Smith the shot-blocking center, Campy Russell the front-court marksman and Jim Chones the rebounding forward. Toss in Fitch's deliberate, patterned, yawn-time offensive philosophy and a bench of scoring specialists like Bingo Smith and Dick Snyder, and suddenly the Cavs had the ingredients to do better than most experts figured.

The Knicks especially had problems with Fitch's tempo caoching. They lost three of four to the Cavs this season and even the return of Spencer Haywood, who had been out a month with a bad knee, might not change that losing trend in this series.

Jim Cleamons, who was supposed to replace Frazier in the hearts of Big Apple fans, has lost his starting berth to Butch Beard. Earl Monroe still has plenty of spin moves remaining and Bob McAdoo can outshoot any center. But young Lonnie Shelton fouls too much and Jim McMillian has never regained his former ability. Also the Kricks usually play defense like McAdoo; badly.

Seattle SuperSonic fans should be patting themselves on the back today. If it weren't for them, their club, which is considered by many the long-shot choice to win the league title, probably wouldn't be in the playoffs.

When those fans stopped showing up for home games in November, the Seattle front office decided a coaching change was necessary. So out went Bob Hopkins and his 5-17 record. In came miracle man Lenny Wilkins, who guided the Sonics to a 42-18 mark the remainder of the season.

The sonics are no flukes. They proved that for all to see when they won at Los Angeles last week in a game the Lakers desperately needed to overcome Seattle and gain a home-court advantage in the playoffs.

Instead, Seattle holds the home-court edge against the Lakers in the best-of-three matchup. And unless Bill Walton returns in a healthy state, the Sonics also may hold an edge over Portland if those clubs meet in the next round.

Walton hasn't suited up since early March when first one foot and then the other began hurting him. He says now that he isn't "spiritually able to play yet" but he will have until at least Sunday, and probably longer, to get that problem straightened out.

A properly motivated Walton makes Portland nearly unbeatable, even with Bob Gross sidelined until early May. But injuries have so decimated the club that it could take Coach jack Ramsay a while to regain the continuity that made the Trail Blazers so impressive the first four months of the season.

And Seattle doesn't give an opponent much room for error. Wilkins somehow has prodded players like John Johnson, Gus Williams and Marvin Webster to their best seasons as pros. He uncovered Dennis Johnson, one of the league's best defensive gurads, persuaded veteran Fred Brown to accept a substitute's role and brough along rookie forward Jack Sikma so well that Sikma now is a rebounding and scoring threat.

While the Sonics finished strongly, the rest of the West stumbled. Denver annually runs out energy by play-off time and the thin Nuggets stayed in form this season. Everytime it appeared Los Angeles was on the right track, the Lkaers would break down defensively and lose. And Phoenix went through a horrendous slump that even Walter Davis and Paul Westphal couldn't cure.

The result was that only five victories separted No. 6 Milwaukee from No.2 Phoenix by season's end. The West playoffs should be just as close, as long as Portland stays mortal.

Los Angeles (45-37) vs. Seattle (47-35)

"When he wants to play, there isn't anyone who can dominate like he can." said Bullet forward Bob Dandridge about former teammate Kareem Abdul-jabbar. "I've seen him control games. But first he has to want to play."

When Abdul-Jabbar has been properly motivated this year, Coach Jerry West's band of L.A. all-stars has been something to behold. But the big center has had more down days than good ones and no Laker is willing to predict how he will approach the play-offs.

An average showing by Abdul-Jabbar probably won't be good enough to handle the Sonics. He has to keep the fast improving Webster away from the boards and out of Seattle's offense. And he has to become involved in the Lakers' team play instead of taking on the entire offensive burden by himself.

When Abdul-Jabbar is the hub of the Lakers' offense, he wheels and deals passes to cutting guards Norm Nixon, Charlie Scott and Lou Hudson or takes those sweeping sky hooks and jumpers. That's when his pressence makes Adrian Dantley so effective underneath.

When unselfish, defensive-minded Don Ford starts instead of Jamaal Wilkes at forward, the Lakers also play better. But West has been going with Wilkes, an offensive threat lately. How he employs these two forwards also will effect the Lakers' chances.

The playoffs represent an opportunity for the Lakers to redeem themselves after a disappointing regular season that began with Abdul-jabbar breaking his hand on Kent Benson's head. Owner Jack Kent Cooke has poured a nice chunk of his wealth into providing West with all-stars; he expects better results from his investment than he received over the last five months.

Seattle can run with the Lakers and the Sonics should be able to exploit L.A.'s rebounding problems, a weakness the Bullets exposed last week in a game at Capitol Centre. Seattle is especially tough on the offensive boards, where the master, paul Silas, still hasn't lost his touch.

If the series evolves eventually into a battle of defenses, the Sonics should benefit. Scott has never been known for his defensive prowess and the Bullets' Wes Unseld scored 25 points against Dantley last week. Hudson is willing but age has taken away some of his quickness.

Phoenix (49-33) vs. Milwaukee (44-38)

The Bucks' season was supposed to terminate Sunday, when the regular season ended.But they refused to wilt down the stretch and, despite a fine challenge by Golden State, hung onto the last West playoff position.

Milwaukee already has accomplished more than Coach Don Nelson expected, especially since he received very little from enson, teh first player picked in the draft. But John Gianelli did an adequate job in the pivot the last half of the schedule and the rest of the young team developed faster than expected.

But not fast enough to handle Phoenix, which devours opponents on this home court. The Suns carried five rookies on their roater, including seventh-round pick Alvin Scott, and this lack of experience caught up with them slightly in March. Yet their first seven players compliment each other so well, they still were able to compile the league's fourth-best record.

Davis and Westphal combine for almost 50 points a game and both are efficient pressure performers. Center Avan Adams finally has overcome a midseason health problem to give more support in the middle, and guards Ron Lee and Don Busse play like The Dirty Dozen on defense.

Milwaukee will have to play nearly mistake-free basketball to compete with the Suns, who thrive on turning errors into fast-break baskets. But young players are prone to make mistakes, especially on the road.

The series-long matchup between those splendid rookies, Davis and Marques Johnson, alone should be worth the price of admission. While Phoenix needs points from Davis to survive, the Bucks ask Johnson to do more: score, rebound (he leads the team) and provide some sort of shotblocking threat underneath.