Aldridge had 48 points and 13 rebounds, and San Antonio ran past Boston 115-96 on Sunday, giving the short-handed Celtics their fourth straight loss.
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, after rebounding well from a tough loss to Houston on Friday night.
Aldridge had his second-highest scoring output of the season. He scored 56 points on Jan. 10 against the Thunder.
''I just tried to play,'' Aldridge said. ''Last game I couldn't play. They doubled me the whole game. I just had to try to find my rhythm. Tonight, they let me play 1-on-1 and I loved it.''
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.
It was the latest frustrating outing for the Celtics (43-31), who held an extended players-only meeting after the game. The locker room wasn't opened to reporters until more than 30 minutes after the final buzzer.
''Winning's hard. Team environments are hard,'' Irving said. ''It's not as simple as listening to everybody else speak about what's going on with the team. ... Nobody's been in my position. Nobody here. So I don't expect anybody to understand that. Nobody can speak on it.
''For me, my focus is figuring out, the guys I have in this locker room, is how to get the best out of them and them get the best out of me.''
Coach Brad Stevens was also delayed before speaking with reporters. He said he opened the floor for players to offer insights into their current struggles, but said it wasn't uncharacteristic for him to seek such input.
''There's some frustration in there,'' Stevens said. ''We don't need to ride the emotional rollercoaster. We need to get a lot better.''
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 Harden in the loss to Houston, the most points scored against San Antonio during Gregg Popovich's tenure as coach.
Popovich's team seemed unfazed by that setback.
Aldridge connected on eight of his first 12 shots against Boston. 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.
''We just need it, Aldridge said. ''It's winning time. It's getting close to playoff time, every game is going to have playoff intensity or implications. It's just a win that we needed tonight.''
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.
Boston 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.
Spurs: At Charlotte on Tuesday.
Celtics: At Cleveland on Tuesday.
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