BOSTON -- Defense has been the Detroit Pistons' calling card for most of the season, but their offense carried them past the Boston Celtics on Wednesday night.

Kentavious Caldwell-Pope led a group of four 20-point scorers for the Pistons, who shot a sizzling 55.2 percent (48 of 87) and notched a season-high in points with their 121-114 victory.

"Over the course of the 48 minutes, no question the best offensive performance of the year," said Pistons coach Stan Van Gundy, whose team entered the night allowing the seventh-fewest points (99.4) in the NBA.

"We're probably like 25th (in defense) now after giving up 114," Van Gundy joked.

Tobias Harris scored 21 and Marcus Morris added 20 for Detroit (10-10), which has won four of its last five games. Ish Smith approached a triple-double with 19 points, eight rebounds and eight assists.

"They made shots when they needed to make shots," Celtics forward Kelly Olynyk said. "They made them four quarters in a row. Obviously we could have made them miss a few more."

Andre Drummond, who received his first career ejection during Tuesday's 112-89 win over the Charlotte Hornets after throwing an elbow at Roy Hibbert, had 20 points and 17 rebounds.

"We can't pinpoint one guy," Drummond said. "Everybody as a collective group is playing hard."

Isaiah Thomas totaled a game-high 27 points and Olynyk contributed 19 points off the bench for Boston (10-8), which has dropped two of three.

Olynyk was on the mend after splitting open his right elbow in the Celtics' 112-104 win over the Miami Heat on Monday.

"It's good," Olynyk said about his elbow. "Obviously tender, split open. (Celtics trainer Ed Lacerte is) doing a good job keeping that under wraps."

Avery Bradley finished with 14 points, but struggled to the tune of 4 of 12 shooting for the Celtics. He was held to three points over the first three periods.

"I wasn't making shots," Bradley said. "I was just able to knock some down a little too late."

Jae Crowder also had 14 points for Boston, which was outrebounded 52-33.

"I think they just wanted it more," Bradley said.

Thomas' jumper with 7:18 on the clock in the first quarter put the Celtics ahead 11-9, but back-to-back buckets from Drummond put the Pistons in the driver's seat until the 7:27 mark of the fourth quarter.

Detroit led 31-28 after one and led by as many as eight in the second quarter. Thomas scored eight in the period and 16 in the first half to keep Boston within striking distance, down 59-53 at halftime.

The Pistons opened a 10-point lead at 90-80 on Jon Leuer's dunk with 1:24 left in the third. Boos rained down from the Garden crowd as the Celtics fell behind 92-84 after three.

"We (were) trying to get it all back at once," Bradley said. "I still like the effort that we played with at the end of the game, all the guys still played hard and tried to win the game."

A couple of Crowder baskets brought Boston within 94-92 with 7:42 to play.

Terry Rozier sank a free throw to finish off a three-point play and give the Celtics a 95-94 lead with 7:27 left, but Marcus Morris hit two free throws at the 7:00 mark to give the lead back to Detroit.

The Pistons didn't trail after that and again stretched their lead to double digits before letting Boston within 118-114 with less than 20 seconds to play.

"We played the game well for 46 and a half minutes," Van Gundy said. "The key to the end was the clock ran out."

Boston won 94-92 in the first meeting of the year with the Pistons at Detroit on Nov. 19.

NOTES: Boston C Al Horford returned to the lineup after missing Monday's win against the Heat due to the birth of his daughter the day before. Horford was criticized by a local radio host for missing the game. "My family's very important to me," Horford said Tuesday. "Everybody has their opinion. I respect anything that anybody has to say." ... Celtics F Jae Crowder no longer has a minutes restriction six games after returning from a left ankle sprain. "Nobody's told me about a minutes restriction since before the Miami game," Boston coach Brad Stevens said. ... Detroit G Reggie Bullock (left knee meniscus tear) is still waiting to receive a second opinion. "Not going as fast as I would like," Pistons coach Stan Van Gundy said. ... Pistons PG Reggie Jackson (left knee rehab) missed his 20th consecutive game. ... Boston hosts the Sacramento Kings and Detroit visits the Atlanta Hawks on Friday.