Need a big basket? Give the ball to Paul Pierce. Sharp passes and solid foul shooting? He provides that, too.

Pierce did all that for the Boston Celtics on Wednesday, expanding his role on an injury-depleted lineup and lifting them to a 102-98 win over the Orlando Magic that clinched the Atlantic Division title.

It came one night after he scored 43 points.

"I wanted to just be aggressive, looking to score, and when they collapse I just wanted to make the easy pass," said Pierce, who had 29 points and a career-high 14 assists with Rajon Rondo sidelined with a sore lower back. "I just wanted to make the right plays when the ball's in my hand down the stretch."

He did that with 7.6 seconds left with a 16-footer from the right elbow. He sank it even though he slipped, giving the Celtics a 100-96 lead as the 24-second clock was about to expire.

"This is unscripted," Pierce said. "I'm not thinking. 'Woo, I slipped let me go take the shot.' It's just something that happens. You play off instincts."

For the second straight night he drove hard to the basket, repeatedly drawing fouls. He sank 17-of-18 free throws in a 118-110 loss to the New York Knicks on Tuesday night then made 11 of 12 against the Magic.

"That's huge for our team," Boston coach Doc Rivers said. "It allows us to set our defense and it's something that we really haven't done well this year."

Boston (37-26) has a 3 1-2-game lead over New York (33-29). Both can end the regular season tied at 37-29, but the Celtics would finish first with a better conference record, the second tiebreaker behind head-to-head matchups.

After the game, Rivers said he told his players, "We were two games under .500 at the All-Star break and the fact that you did it and did it this early I think is very impressive."

Division winners are guaranteed to be seeded no worse than fourth in the conference and wouldn't have to face Chicago or Miami in the first round.

Avery Bradley started for Rondo and finished with 23 points. Brandon Bass added 21.

Glen Davis, starting in place of Dwight Howard, led Orlando with 27 points. Jameer Nelson had 19 points and nine assists.

"There's been multiple games where we've been down and we just went away," Davis said. "I like how we fought today but, at the end of the day, we need to win the game."

Howard missed his sixth consecutive game because of a herniated disc and the Magic missed his defense as the Celtics hit 54.3 percent of their shots.

"Our effort was great. We just can't guard anybody," Orlando coach Stan Van Gundy said. "Our 3-point shooting again was horrendous. We had the one possession to tie in (the last) two minutes and we missed two open ones."

The Magic cut a 91-78 lead to 91-90 on a layup by Nelson with 3:04 left. But they came no closer as Pierce and Ryan Anderson traded one free throw each. Pierce hit a short jumper in the lane, Bass caught Pierce's shot that missed the rim and put in an easy layup and Kevin Garnett made a free throw for a 98-92 lead with 1:31 remaining.

But Orlando, sixth in the Eastern Conference at 36-26, fought back on baskets by J.J. Redick and Davis, making it 98-96 with 31 seconds to play.

Pierce then hit his 16-footer. After a basket by Nelson, Pierce sealed the victory with two free throws.

"Paul is not flashy," Rivers said. "I don't even know how Paul scores sometimes. He doesn't look like he's that quick but he is. He's got a gift. He's a professional scorer."

The Celtics played without their starting backcourt. Point guard Rondo, who has at least 10 assists in each of his last 23 games, had a sore lower back after landing hard on it Tuesday night. Pierce also fell hard in the game, hurting his elbow but said he knew Wednesday morning he would play. Ray Allen missed his sixth straight game with a right ankle injury.

Pierce tied his career high with his 13th assist with 4:37 still left in the third quarter. He got his 14th with 9.5 seconds left in the period, feeding Bass for a jumper from the left corner.

Trailing 67-59, Orlando scored the next nine points to take its first lead since 6-5. It stayed on top 70-69 before the Celtics finished the third quarter with a 10-0 run that gave them a 79-70 lead. Bass scored six points and Pierce had four in that comeback.

The Celtics led 33-22 after one quarter, starting the game with nine baskets on their first 11 shots. But the Magic cut that to 55-51 at halftime with the help of their 3-point baskets — three by Nelson and one by J.J. Redick.

Notes: Orlando outrebounded Boston 51-37. ... The Celtics observed the 50th anniversary of the fifth of their 17 world championships with a halftime ceremony. Seven members of the team that beat the Los Angeles Lakers 110-107 in overtime to clinch the title were introduced — Bill Russell, Bob Cousy, Tom Heinsohn, Sam Jones, Tom Sanders, Jim Loscutoff and Frank Ramsey. ...Davis, traded by Boston before the season for Bass, scored Orlando's first three baskets.