Boston, MA -- (Sports Network) - Paul Pierce had nine of his season-best 39 points in overtime, as Boston beat Toronto, 115-109, sweeping the season series against the Raptors for the first time since the 1997-98 season.

Pierce, who went 13-of-26 from the field, also had nine rebounds, as the Celtics won back-to-back contests after a season-high four-game skid. Kevin Garnett tallied 20 points and 12 rebounds.

"You all need to start playing some of that superman theme music in the building when he's going like that," said Garnett of Pierce during the postgame news conference. "This is Clark Kent right here ladies and gentleman.

"I'll be Batman, I'll be Robin, I'll be anybody you want me to be. I'll be the garbage man. But this is Clark Kent right here."

Andrea Bargnani had 23 points and eight boards for the Raptors, who were 94-88 home losers to the Celtics on Sunday. Chris Bosh ended with 18 points and 11 rebounds, and Roko Ukic scored 16 as the Raptors faltered again after coming into the home-and-home set having won four of five games.

The Raptors forced overtime thanks to a clutch shot by Bargnani, as he drained a three-pointer with one second left from the left side. Rajon Rondo's tip try for Boston was off the mark at the end of regulation, with the game remaining even at 93-93.

Pierce banged in a three to start the OT, and after Anthony Parker drained a jumper Pierce hit another shot and Rondo's bucket made it 100-95.

"We started off with two costly turnovers, and you can't do that against a team like Boston," said Parker. "But we were being aggressive, trying to do some things that didn't work out. I think we stopped them a couple of times in a row too. They made some big shots, some contested shots, and that was the main difference."

Ukic's layup had the visitors within 100-97, but Ray Allen nailed a three- pointer with just over two minutes remaining, and Toronto didn't get closer than four the rest of the way.

The Raptors were within 113-109 after Parker's long three-pointer, and they stole the inbounds pass, but Jason Kapono missed a shot from behind the arc in the waning seconds.

"Actually, I feel pretty good, could have played another quarter, I think. I'm feeling pretty good," said Pierce.

Toronto led 23-19 after one quarter and stretched that to 54-45 at the half before Boston rallied in the latter stages of the third quarter, getting within 71-69 on a Pierce spin move to the basket. The Raptors led 78-74 heading to the fourth quarter.

Game Notes

New Red Sox pitcher John Smoltz was in attendance. He will be introduced by at a Tuesday morning press conference...Celtics center Kendrick Perkins is expected to be sidelined the next week due to the recurrence of a left shoulder injury he suffered during the NBA Finals. Brian Scalabrine started at center Monday night and had 11 points...The Celtics also played without guard Tony Allen. He was wearing a protective boot on his strained right ankle and is also expected out until next week...Raptors guard Jose Calderon was out due to a strained right hamstring...Parker had 11 points and Will Solomon scored 10 for Toronto, while Ray Allen scored 12 and Leon Powe 10 for the Celtics.