The Celtics’ Paul Pierce battles for a loose ball with the Hawks’ Marvin Williams during the first quarter of last night’s game at TD Banknorth Garden. Pierce finished the game with 34 points as Boston handed Atlanta its first loss of the season.

AP / Michael Dwyer

BOSTON — Paul Pierce did it again.

With the game on the line for the second straight outing, the Celtics turned to their captain and the man they call The Truth. And once again he delivered a clutch fourth-quarter performance.

One game after willing Boston past Toronto with a 22-point, fourth-quarter effort, Pierce scored 34 points last night, with the biggest two coming with 0.5 seconds left on the clock.

That’s when he knocked down the game-winning basket, a high, arcing, 20-foot jumper from the right wing that gave Boston (8-1) a thrilling 103-102 victory over previously unbeaten Atlanta (6-1).

“The last play was drawn up to get the ball to Paul Pierce and get the hell out of the way,” Boston forward Kevin Garnett said. “Superman’s in the booth. Let’s go home. That was the play, and if you don’t believe that, ask Doc Rivers and he’ll say the same exact thing.”

Pierce said the play was drawn up a little bit different than that.

“Once I went right, I had the big guy on me, I sort of got to my sweet spot and I felt good the whole time,” Pierce said. “The play was to get the ball to Kevin [Garnett] and if they switched off, either hand off or he would take the drive down the lane. They switched and put [Al] Horford on me and I knew I could get to my spot. I got it, and thank God it went in.”

The Hawks came into the game with a chip on their shoulders.

They were looking to avenge their opening-round playoff loss in seven games to Boston last year.

Several of the Hawks, including head coach Mike Woodson, said that Atlanta’s series against Boston in the playoffs last year gave the Hawks the confidence to believe that they are one of the NBA’s elite teams this year.

“That was the biggest turning point of our basketball team, pushing [the Celtics] to seven games,” Woodson said.

“They put us in that mode, that frame of mind, that you know you’ve got to come out every night and dig in and play man,” Woodson added.

The Hawks entered the game tied with the Los Angeles Lakers for the best record in the NBA, but Boston refused to let Atlanta win on the parquet floor of the TD Banknorth Garden, where the Celtics have not lost a game all season.

Rajon Rondo brought the crowd to its collective feet when he buried a 21-foot jump shot from the right wing to put Boston ahead, 96-92, with 2:09 remaining in the game. Maurice Evans answered with a 3-pointer for Atlanta to make it a one-point game.

On Boston’s ensuing possession, Pierce drove through the lane, connected on a layup, and was fouled by Evans.

With nearly the entire crowd chanting “MVP,” Pierce knocked down the free throw to give Boston a 99-95 cushion.

The Celtics got a stop, but a Mike Bibby steal gave Atlanta new life.

They put the ball in the hands of two-time All-Star Joe Johnson, who was fouled by Pierce on a drive to the basket.

He sank both free throws to cut Boston’s lead to 99-97 with 1:01 remaining. Atlanta called a timeout and forced Boston into a bad shot to regain possession of the ball. Johnson then connected on a 13-foot running jumper to tie the score at 99-99 with 33.6 seconds left.

The Celtics called a timeout with 29.4 seconds left and chose to clear the lane for Pierce to take Johnson to the basket, one-on-one. Johnson fouled Pierce who went to the line and knocked down both free throws amidst more MVP chants to put Boston back on top, 101-99, but Marvin Williams took the life out of the crowd when he stroked a 3-pointer from the right baseline, giving Atlanta a 102-101 lead with 7.4 seconds left.

That set the stage for Pierce’s game-winning shot.

“It was a great shot by Paul,” Rivers said.

“A great player hit a great shot, but I applaud my guys, you know, we never quit,” Woodson said.

Garnett (25 points, 12 rebounds), Ray Allen (17 points, 7 rebounds), Kendrick Perkins (9 points, 8 rebounds) and Rondo (5 points, 10 assists) all played well for the Celtics, who overcame a 16-point, first-half deficit.

“I thought our starters came out and played great,” Rivers said.

Johnson (28 points, 7 assists), Bibby (16 points), Williams (14 points), Flip Murray (14 points), and Evans (13 points, 5 rebounds) all scored in double-figures for the much-improved Hawks, who are one of the NBA’s top defensive teams this year and are hoping to take away Boston’s title this year.

“Until these guys are dethroned, they are the world champions still,” Woodson said of the Celtics. “We’re trying to get where they are. That’s the ultimate goal.”

roblee@projo.com