Gasol stole the ball from Ray Allen and then hit a layup with just over a minute left to put Memphis ahead 88-85. After Gasol missed a pair of free throws with 4.6 seconds left and a chance to go up by five, Paul Pierce missed an off-balance 3-pointer that would have sent the game into overtime.
The victory helped Memphis solidify its hold on the eighth and final playoff spot in the West. The Grizzlies (40-32) are just one-half game behind seventh-place New Orleans.
The Celtics (50-20) missed a chance to move into a tie with Chicago for the best record in the Eastern Conference.
Pierce scored 22 for Boston, which lost for the fifth time in nine games. Rajon Rondo had six points, seven steals, 11 rebounds and 11 assists.
Memphis led 84-77 in the fourth quarter before Boston cut the deficit to one point, 86-85, with under 3 minutes left on Pierce’s 3-pointer. Gasol made it a three-point game before Glen “Big Baby” Davis made a jumper with 52 seconds left to cut the lead to one point.
Rondo rebounded a Memphis miss and brought the ball the length of the court before floating up a one-handed shot that bounced off the back of the rim. The Celtics sent Mike Conley to the line with 14 seconds left and he made both free throws.
Davis’ 3-point attempt to tie it missed, but after Gasol was fouled he missed both free throws. Boston inbounded the ball but Pierce couldn’t get off a good shot.
After falling behind 36-26 in the second quarter, the Celtics scored eight straight points — including back-to-back 3-pointers from Allen— to make it a two-point game. It was 38-34 when Boston again scored eight in a row to take the lead before Memphis scored twice in the final minute to make it 45-44 at the half.
Notes: Former Celtics Leon Powe and Tony Allen received a warm welcome from the crowd at introductions. … Ray Allen wore a bandage above his right eye. He received seven stitches after being elbowed by Jared Jeffries in Monday night’s game against the . Allen and Pierce are the only Celtics to play in all 70 games this season. … The Grizzlies said on Tuesday that No. 2 scorer Rudy Gay would miss the rest of the season to have surgery on his partially dislocated left shoulder.