The Boston Celtics were at the bottom of the National Basketball Association two seasons ago before they signed a self-proclaimed hick from Fench Lick, Ind., named Larry Bird. He flew them upward, finally reaching The Summit tonight in Houston as the Celtics won their 14th NBA championship with a 102-91 victory over the game, but overmatched, Rockets.

This series wasn't expected to go beyond five games, but the Rockets slowed the tempo in each contest and stretched it to six games.

Bird had not been having a particularly good series, until tonight, averaging only 13 points and shooting 38 percent. But his determination, three baskets and the drawing of a charging foul, all in the last four minutes when the Rockets were closing fast, enabled the Celtics to regroup and come away with the 11-point victory.

Bird finished with 27 points, 13 rebounds and five assists.

Teammate Cedric Maxwell, who scored 19 points and was the steadiest Celtic throughout the series, was named the most valuable player.

"This is the first time I've ever won a championship on a major level and there just isn't anything to describe it," said Maxwell. "There is no real way I could explain about how I feel or how I played and how I contributed. But overall it was just a team victory and we won it with a lot of hustle and a lot of pride."

"I feel as much relief as anything," added Bird, "because we came in it supposed to win because we were the Celtics and everyone said, 'Who is Houston?' We knew if we played hard we'd win."

Boston appeared to have the title won when Robert Parish's turnaround jumper gave his team an 84-67 lead with only 10 minutes to play.But the Rockets, who made it to the final after a 40-42 regular season by not departing from their tactics of slowing the pace, abandonend all that was familiar to them and almost pulled off another miracle.

They pressed full court, and ran fast breaks at every opportunity. All of a sudden it was a ball game again. The Celtics missed eight straight shots and went scoreless for 4 minutes 48 seconds as the Rockets ran off 11 straight points and 16,121 people had the building rocking.

A driving fast break basket by Tom Henderson closed the Rockets to 86-83 with 4:28 remaining.

But Bird countered with a 15-footer from the baseline, hustled up court to draw a charging foul against Henderson, then sank a 22-footer -- and the Celtic lead was back to seven, 90-83, with 3:34 to play.

Houston rookie Calvin Garrett, who came in to score eight points that period, made an 18-footer that got the Rockets back within three again, 92-89, with 1:51 left.

Then came perhaps the biggest basket of the game. Bird got free in the left corner, a half-step from the sideline and sank a three-point shot.

"I never hesitated," Bird said. "That corner shot is no farther than most of my shots."

The Rockets never recovered, getting only one more basket, and were forced to foul to get the ball. The Celtics scored their last seven points from the free throw line.

"There was never no doubt we were going to win," said Bird."Why? Because they were calling my play. They went to me everytime down the stretch. Sometimes I came through and sometimes I didn't."

All five Celtic starters scored in double figures.

The Rockets got 27 points, eight rebounds and five assists from Robert Reid and 23 points and 16 rebounds from Moses Malone, but they simply didn't have the players to compete with the Celtics.

This was the type of game in which they could have used the talents of Calvin Murphy, but the guard separated his shoulder in Game 5 Tuesday in Boston and sat on the bench in his street clothes tonight.

The Rockets scored the game's first six points, but the Celtics never lost their poise. Parish scored 10 of their first 19 as they rallied for a five-point lead. The Rockets cut it to 25-24 by the end of the period.

The Celtics had increased the lead to 53-47 by haltime, then ran circles around the Rockets in the third period, making 13 of 18 shots and moving to a 82-67 lead.

Bird had eight points, five rebounds and two assists in the quarter.

The only change in strategy by either coach was made by Houston's Del Harris, who put Malone on Maxwell and Billy Paultz on Parish. He did it because, in the previous game, Maxwell killed the Rockets with 28 points and 15 rebounds. He took Paultz inside and worked him over while Parish went outside and took Malone away from the basket.

By putting Malone on Maxwell, Harris hoped to keep his star center closer to the basket.

The Celtics are the first team since the 1972 Los Angeles Lakers to finish with the best regular season record and win the NBA championship, too.

The Celtics received a playoff total of $398,500 or $33,208 per person, based on 12 shares (11 players and a coach). The Rockets will divide $295,000.

The Celtics won only 29 games two seasons ago, but won 61 a year ago, the best in the league, and 62 this season, tying Philadelphia for the most regular season victories.

The last Celtic title was in 1976.