Last spring, after defeating Houston to win the National Basketball Association championship, the Boston Celtics were properly proclaimed the best team in all of basketball.

They had put together back-to-back 60-victory seasons and had overcome a seemingly insurmountable 3-1 deficit against Philadelphia in the Eastern Conference finals.

Now, at the midpoint of another season, the players and their coach believe that they are better than last year, when they were 62-20 in the regular season and beat Chicago, Philadelphia and Houston in the playoffs. Boston's current record is 31-11.

Can the Rolling Stones sound better? Can Rodney Dangerfield be funnier? Can the Celtics get better?

"We're better team than we were last year," said Robert Parish, one of the essential ingredients added to this team. We are more experienced and a lot more confident. Kevin (McHale) has been here a year, I've been here a year, we're both a lot more comfortable.

"Defensively, our front line has really improved. We all know where everybody will be at all times. If anybody gets caught out of position, he knows he'll get help. That's very important.

"Offensively, there is no hestitation about giving up a shot and making the extra pass. I look around and I know that whoever is out on the court helped us win a world championship. I have a lot of confidence in all my teammates because we've been through it all before and we've been successful."

Confidence appears to be a big difference between this year's edition of the Green, as the players call themselves, and last season.

"Last year we were the hunter, now we're the huntee," said glib M.L. Carr, the versatile reserve who often serves as a thoughtful spokesman. "There's a lot more pressure on the hunter than the rabbit. We can just run and play our games and it's up to the others to try and catch us."

In recent NBA seasons, the rabbits haven't run fast enough. The defending champions have followed a pattern of finishing the succeeding season with the league's best record only to lose in the playoffs.

After Golden State swept the Washington Bullets in 1975, the Warriors led the league with 59 victories next season. Boston won the championship that year, but slipped to 44 victories the following season when Dave Cowens went home for Christmas.

The next two years, Bill Walton's Gang won in Portland and followed up with a league-leading 58 victories before the redheaded center's injury ruined their playoff plans. The Bullets were champions in '78 and led the league with 54 victories the following season before blowing a return match with Seattle in the finals. Seattle came back with 56 victories, but finished behind the champion Los Angeles Lakers. A knee injury to Magic Johnson destroyed the Lakers' hopes of repeating, but now the Celtics seem headed for the best record this season after winning 30 of their first 39.

"There's no doubt that confidence plays a big part for us," Coach Bill Fitch said after the Celtics held off a Knicks' rally for a four-point victory in New York.

"In close games our players believe they'll find a way to win," the coach continued. "You don't win 60 games two years in a row without winning a lot of close games. A lot of teams will panic in front of a big crowd, but we play to sellouts every night at home (46 in a row and counting) and usually have big crowds on the road. We're used to it.

"We don't lack for confidence. We know what we've been through, we know what we accomplished last year. It has a lasting effect."

The only thing that can destroy confidence is failure and it seems highly unlikely that will befall the Celtics as long as Larry Bird is healthy and performing up to his exceptional capabilities.

The versatile all-star forward is the one the Celtics turn to in the final minutes of close games. Last week he scored six of his team's last eight points in a 111-107 victory at New York, then had eight in a row after Indiana closed within six (101-95) with five minutes to play the following night.

"We know by now," said McHale, the rapidly improving second-year forward, "that when things get tight you play good defense and look for Larry."

During a recent seven-game stretch that included a season-high 40 points against Detroit, Bird averaged 32.2 points, 14.1 rebounds, 9.1 assists and three steals. He made 99 of 161 shots (.614).

"Having Larry out there really makes a difference," said. Tiny Archibald, the still-quick playmaker in charge of the Celtics' offense. "He's very difficult to stop because he can go inside or he can go outside.

"Right now people are trying to take his drive away, so he's taking his outside shots and making them."

Bird, still self-effacing, answers first with a shrug when asked about his outside shooting success.

"I don't know what I'm doing so right on my shot," he says. "If I did, I'd keep it up all year. I do know that as long as I'm hitting, I'm going to keep shooting. I don't think I'm hurting the team by scoring 30 or 35 points a game as long as I'm hitting. If I'm shooting 10 for 25 or something, that's when I'm hurting the team."

The only way Bird could hurt the Celtics would be by taking a Caribbean cruise next month. Make no mistake: he is the difference between a very good team and an excellent one.

"The way Larry is playing makes it a lot easier on the rest of us," said Cedric Maxwell, who returned last Wednesday after missing four games because of a sprained right knee. "Late in the game the other team is so conscious of him that the rest of us have a better chance of getting open. And if we're open, Larry will get us the ball."

Maxwell is a prime example of the Celtics' depth. While he was out, McHale took over his forward spot and averaged 21 points and nine rebounds a game.When Parish needs a rest, Rick Robey is effective in the pivot. When archibald sits down, Gerald Henderson can direct the offense.

"The way Kevin's been playing, he should keep starting," said Maxwell, a regular since his rookie season four years ago. "He's playing the same role I was, getting his points off the offensive boards and playing good defense. We have a lot of depth, that's way we don't get in losing streaks."

Perhaps the Celtics' most remarkable achievement this season is the fact that they have yet to lose two games in a row.

"We've got great depth, that's why we're so consistent," said Carr.

In addition to McHale and Parish, who have progressed so much from last year, the Celtics' improvement is personified in Henderson's play. The three-year veteran from Virginia Commonwealth has the quickness and versatility to play both guard positions.

"I know have a lot more confidence this year," he said. "Now I just go out and do what I can do. I go full speed and don't worry about making mistakes anymore. I'm still learning, but now when I go in, I know I can do my job."

Confidence, experience, depth and a superstar all are necessary qualities for an NBA champion. Even then, a team can fall short if the chemistry isn't right. When players spend more time together during an eight-month period than they do with their families, they have to get along.

"We're a very happy team and happy teams win," said Parish, who admits such a spirit was missing during his four years with Golden State. "Everyone pulls together, there isn't any finger-pointing and nobody get down on anybody."

There is plenty of needling, though, on those seemingly endless bus rides and those interminable waits for luggage at airports.

When Chris Ford was singing a few bars of Sister Sledge's "We are Family," Bird yelled, "If we're a family, Ford, you're the grandfather."

When recently signed rookie Danny Ainge of Brigham Young, who quickly earned his teammates' respect with his hustle in practice, used a bit of strong language on a bus ride, M.L. Carr admonished him. Carr said Jeff Judkins, a former teammate of Ainge's at Utah, never talked like that when he was with Boston."Maybe he was an Orthodox Mormon," Carr added.

"This is the same atmosphere I knew in college," said Bird, who helped Indiana State reach the NCAA final, where it lost to Michigan State and Magic Johnson. "Everybody is always razzing everybody else. It's really important, too, because it keeps everybody loose."

"It all comes from within," said McHale, giving credit to management -- especially General Manager Red Auerbach. "We have a strong organization and the players are treated well... We have a great blend here and we know it works."

Will it work well enough for the Celtics to become the first NBA team since 1969 to successfully defend an NBA championship?

"Since way back when the Celtics did it, no other team has repeated," said Archibald, a 12-year veteran. "I think we can do it. All of us do... but we're definitely on a Mission Impossible."