The Los Angeles Lakers will become the first team to make it to this season's quarterfinals of the National Basketball Association playoffs if they beat the demoralized Phoenix Suns today in Phoenix.

Playing without Truck Robinson, their only established rebounder, the Suns are down, 3-0, going into today's fourth game of the best-of-seven Western Conference semifinal series.

The Lakers won the first two games at the Forum as expected, then stunned the Suns, 108-105, Friday night in Phoenix.

Kareem Abdul-Jabbar scored 15 points in the final period, 37 overall, to pace the Lakers.

Without Robinson, who twisted a knee in the first round of the playoffs against Kansas City, the Suns have been intimidated.

In the other West semifinal series, the surprising Milwaukee Bucks will try to stretch their 2-1 lead over Seattle in Milwaukee.

The Bucks split two overtime games with the defending NBA champion Sonics in Seattle, then downed Seattle, 95-91, at home Friday night.

The big man for Milwaukee has been 6-foot-11 center Bob Lanier. He scored 24 points Friday and since the Bucks acquired him from Detroit, they have won 28 games and lost only seven.

Rookie Sidney Moncrief also has been outstanding. He scored all six of Milwaukee's overtime points when the Bucks won in Seattle, and has scored 37 points in the three games, despite limited playing time.

In the Eastern Conference, Atlanta will try to even its semifinal series with Philadelphia at 2-2 tonight at the Omni. The 76ers have won only one game there the last two years.

The Boston Celtics had little trouble beating Houston twice in Boston in the first two games of their series. The series moves to the Summit for game three today and game four Monday but there is little hope for the Rockets. The Celtics won all three regular season games in Houston this season.

The best shooters and ball handlers in the league deservedly get the headlines, but who were the worst shooters and ball handlers in the NBA?

The worst shooter of all was Delmer Beshore of Chicago with 35.2 percent.

He was followed by John Brown of Atlanta (36.4), Paul Silas of Seattle (37.8), Willie Smith of Cleveland (38.4) and Jack Givens of Atlanta (38.5).

The players with the most turnovers were: Michael Ray Richardson of New York (359), Reggie Theus of Chicago and Magic Johnson of Los Angeles (305), Moses Malone of Houston (300), Abdul-Jabbar of Los Angeles (297), Mickey Johnson of Indiana (286) and Julius Erving of Philadelphia (284).

Boston Celtic Coach Bill Fitch's reaction to Ralph Sampson's decision to stay at Virginia:

"I've got a film of the Ohio State-Virginia game and there's a play where Ralph Sampson leaps to the ceiling. I mean his feet are as high as the other guys' belly-buttons.

"Well, he gets his legs cut out from under him, but there's a guy underneath him when he falls so nothing happens. It was one of those 'Oh, my God' things. If he does that again, and there's no one under him, I hope those people and profs in Virginia who deal in theory instead of the real world can pick him up and tell him why he shouldn't have joined the Celtics.

"I think it was the dumbest thing I've heard yet. Somewhere down there among those great educators, there must be someone who can tell him of this opportunity. My thinking is that it can't be a final decision. It wouldn't surprise me at all if he reconsidered."

Arkansas Coach Eddie Sutton has withdrawn his name as a candidate for the coaching job of the new Dallas franchise. The leading candidate appears to be Cotton Fitzsimmons, who is not happy in Kansas City. His contract is also up . . . Dallas may be put at a great disadvantage in the dispersal draft because existing teams can freeze eight players, but Dallas was given a break on free agents. It can pick any unprotected free agent and if that player signs with Dallas, no compensation will be awarded. "That could make us potentially the best expansion team ever," said the Dallas director of player personnel, Rick Sund. . . . At last count there were 56 free agents in the league and a number of them will be in demand -- and probably get enormous salaries.

The best of the free agents are Dave Meyers of Milwaukee. Tiny Archibald, and Cedric Maxwell of Boston, Leon Douglas of Detroit, Larry Kenon of San Antonio, George Johnson of New Jersey, and Fred Brown and Gus Williams of Seattle.