BOSTON -- Brad Stevens turned to Marcus Smart in hopes of sparking a flatlining defense, but Smart wound up jolting the offense instead.

Smart scored eight of Boston's first 19 points and Isaiah Thomas carried the torch from there as the Celtics ran the New York Knicks out of the gym in a 115-87 blowout on Friday night.

"It means a lot for me, it means a lot for this team just to be able to come out and contribute on both ends," said Smart, who stuffed the stat sheet with 12 points, 10 assists, six rebounds and three steals.

Thomas finished one shy of his season high with 29 points and has now scored at least 23 points in all nine games for the Celtics (4-5), who halted a three-game skid.

Boston had surrendered 118 or more points in a trio of losses to the Cleveland Cavaliers, Denver Nuggets and Washington Wizards.

Kelly Olynyk scored 19 points and Avery Bradley added 15 for Boston, which got to the free-throw line an impressive 43 times and made 27.

"We're always trying to get paint attacks," said Stevens, the Celtics' coach. "But we weren't trying to play any different offensively, necessarily."

The Celtics were allowing 108.6 points per game coming in, tied for the fourth-worst mark in the league.

That's why Stevens called on Smart, who made his first start of the season after missing three games early on with a left ankle sprain.

Smart's first assignment? Guarding Carmelo Anthony.

Anthony finished with 12 points, all in the first quarter, before being ejected after picking up a pair of technical fouls late in the first half.

"Bad language," referee Tony Brothers said was the reason for his decision to eject Anthony.

Knicks coach Jeff Hornacek said he wasn't given an explanation for Anthony's tossing.

Anthony did not stick around to talk to reporters after the game.

Brandon Jennings was also ejected after receiving a pair of technicals in the fourth, and Kristaps Porzingis and Joakim Noah were also T'd up.

"I can't comment on that stuff, except for some of those I don't blame the guys," Hornacek said.

Porzingis had 14 points to lead New York (3-6), which lost for the fourth time in six games and has dropped four of its last five meetings with the Celtics.

Smart's offense helped the Celtics get going, but his defense proved to be contagious as well.

The third-year guard from Oklahoma State hit a pair of 3-pointers as Boston built an early 11-point lead in the first quarter.

Inspired by Smart, the Celtics played with defensive energy in forcing four turnovers in the first 5:13.

"Marcus played very hard tonight," Bradley said. "He helped our team out on both ends of the floor."

But the gears started turning for the Knicks as Anthony scored eight during a 19-9 run which brought New York within a point.

The Knicks pulled within 31-27 entering the second quarter.

The perennial All-Star's night would be short-lived, as Anthony was sent to the showers after his double technical with New York trailing 44-38 with 4:44 left before the break.

Anthony was 5 of 8 from the floor in his 12-plus minutes.

"When he gets kicked out early like that, he was playing well. We were hanging in there in the game," Hornacek said. "They got off to a hot start, but then we climbed back into the game."

New York stayed within striking distance in the second quarter, never trailing by more than 13 points thanks in part to a 19-8 advantage on the boards.

"We've got to get the glass better than we did at the start of the second quarter," Stevens said. "That was not good."

Without Anthony, however, the Knicks struggled to score and the Celtics turned a 61-51 halftime lead into a rout in the second half.

NOTES: Boston C Al Horford (concussion) missed his fifth straight game but will travel to Indiana for Saturday's contest with the Pacers. "It's a really good sign," Horford said. Horford returned to practice Thursday and participated in non-contact activities. F Jae Crowder (left ankle sprain) missed his fourth straight game, but coach Brad Stevens did not provide any updates. ... New York F Carmelo Anthony doesn't plan to sit out one half of back-to-backs this season. "I don't really have any kind of negative effect," said Anthony, who did so last year as a precaution returning from a knee injury. The Knicks visit the Toronto Raptors on Saturday. ... Celtics G Demetrius Jackson was assigned to the Maine Red Claws of the NBA D-League on Thursday. ... Boston Red Sox right fielder Mookie Betts visited the Boston locker room before the game. ... The Celtics honored veterans in attendance throughout the night in honor of Veterans Day.