The Spurs have won 10 of 12 to strengthen their grip on a Western Conference playoff spot. San Antonio (43-31) is eighth in the conference, a half-game behind Oklahoma City and Utah.

Aldridge had his second-highest scoring output of the season. He scored 56 points on Jan. 10 against the Thunder.

Marcus Smart led the Celtics with 14 points. Kyrie Irving had 11 points and 12 assists, but was just 5 of 17 from the field. Irving left the game briefly and went to the locker room in the first quarter with an injury to his left hand, but returned and played the rest of the way with tape on his left ring finger.

San Antonio led by 16 less than two minutes into the fourth, and the lead grew as high as 25 in the final period.

The Spurs allowed 61 points to Houston’s James Harden in a loss Saturday night, the most points scored against San Antonio during Gregg Popovich’s tenure as coach.

Popovich’s team seemed unfazed by the setback.

Aldridge connected on eight of his first 12 shots. He had 20 points less than 10 minutes in and finished the half with 25 to help San Antonio take a 54-47 lead.

Boston’s defense had little for Aldridge, who finished 20 of 31 from the field in 37 minutes. He was pulled with 1:35 remaining after picking up his fifth foul.

The Celtics got Gordon Hayward back from a concussion and Aron Baynes returned after missing a game with a left ankle sprain.

Jayson Tatum (back contusion), Al Horford (left knee soreness) and Robert Williams III (back soreness) all remained sidelined for a team that trails fourth-place Indiana by two games in the East standings.

TIP-INS

Spurs: It was Aldridge’s seventh career 40-point game. … He has 27 double-doubles on the season. … Had 32 assists and just eight turnovers.

Celtics: Smart’s 14 points was the fewest points for a Boston leading scorer in a game this season. … Connected on just 40 percent of their field goal attempts (38 of 94). … Irving’s 18 games of 10-plus assists are the most by a Celtics player since Rajon Rondo had 27 such games in 2012-13. … Signed C Greg Monroe to a 10-day contract.