Jayson Tatum of the Celtics and Enes Kanter of the Celtics dive for a loose ball Sunday night during Portland’s 129-119 win at TD Garden. Michael Dwyer/Associated Press

BOSTON — CJ McCollum scored 10 of his 33 points in the fourth quarter and Portland held on for a 129-119 win over the Boston Celtics on Sunday night, extending the Trail Blazers’ winning streak to four.

Damian Lillard had 26 points and 13 assists for Portland. Carmelo Anthony finished with 13 points – including a 3-pointer with 1:08 remaining to help seal it after Boston pulled within two points.

The Trail Blazers improved to 4-0 on their six-game road trip. They entered the game in seventh in the Western Conference playoff standings and are trying to work their way out of the play-in round.

“I think we’re playing better basketball at the right time,” McCollum said. “Understanding the severity of each game – what we need to accomplish heading into the playoffs and what we need to accomplish to get into the playoffs is very important.”

Jayson Tatum scored 33 points to lead Boston, which dropped a game behind Miami for sixth place in the Eastern Conference with seven games remaining. The Celtics will host Miami twice in the next nine days.

“We need to just take the mindset of whether we won or lost, you can’t change that,” Tatum said.

After rallying from 32 points behind to beat San Antonio in overtime Friday night, the Celtics couldn’t produce another comeback against the Blazers, who shot 52% (44 for 85). The Blazers also helped themselves by forcing 18 turnovers and committing only nine.

“I think the biggest thing is I thought we were very aggressive on the ball,” Portland Coach Terry Stotts said. “We created turnovers in a variety of ways. But I think the pressure on the ball, our hands and our alertness on the weak side all played a part in it.”

Norman Powell scored 23 points, Robert Covington had 10 and Jusuf Nurkic pulled down 11 rebounds for Portland.

After the teams went into halftime tied at 71, Portland capitalized on six turnovers in the third quarter and led 103-98 entering the fourth quarter.

Tristan Thompson appeared to put the Celtics ahead on a put-back dunk midway through the fourth, but the basket was incorrectly waved off because of offensive interference. The Blazers, who led 107-106 after the call that was widely disputed by the Celtics and their fans, got back-to-back 3-pointers from McCollum and Anthony for a 113-106 lead.

The Celtics stayed within a basket or two and had another chance after Tatum hit a pair of free throws to pull Boston within 121-119 with 1:21 left to play.

But Anthony answered for Portland with a 3-pointer, then sidestepped his way back on defense while waving his arms at Boston’s fans. After a miss by the Celtics, Powell took it the other way for a layup and Portland had a 126-119 lead.

Aaron Nesmith, who scored 16 for Boston, said the Celtics had some difficulties staying consistent on defense.

“In the second half we were able to pick it up, but we’ve got to be able to do it for 48 minutes,” Nesmith said.

TIP-INS

Trail Blazers: Lillard led all scorers with 11 points in the first quarter. … Anthony needs 10 points to pass Elvin Hayes (27,313) for No. 10 on the NBA’s career list.

Celtics: Guard Kemba Walker (left oblique strain) missed his fourth straight game. Coach Brad Stevens said the Celtics hoped to have Walker practicing again by Tuesday and possibly playing again Wednesday at Orlando. … Marcus Smart finished with 11 points, eight assists and eight rebounds before he was ejected with 1:56 left after receiving a technical foul because of a collision with Nurkic, who was called for an illegal screen. … Jaylen Brown, a game-time decision because of a right ankle sprain, finished with 16 points and 11 rebounds, but both Brown and Tatum went to the the locker room with less than a minute remaining after they collided with each other. … Evan Fournier scored 21 points.