MEMPHIS, Tenn. -- Not so long ago, Zach Randolph was starting for the Memphis Grizzlies.

That Randolph was a double-double machine. But this version, the one coming off the bench, is still capable of carrying a club.

He did it again Sunday night, posting a double-double with 25 points and 13 rebounds as the Grizzlies rallied from a 21-point deficit for a 101-98 victory over the Boston Celtics at FedExForum.

For Randolph, it was his third game of 24 or more points in the last four and his second double-double in the last four.

When the Celtics went on a 19-1 run in the first quarter and it looked like the Grizzlies were about to get run out of their own building, fans behind the Memphis bench became chanting for him: "Z-Bo, Z-Bo!"

"It felt pretty good," Randolph said with a grin.

"Zach put us on his shoulders again," Memphis coach Dave Joerger said. "Especially in the first half when we were struggling and he kept us close."

Down 34-16 after a quarter and trailing 53-38 at halftime, Memphis flipped the score and outpointed Boston 63-45 in the second half.

"We let them punk us and push us wherever they wanted to go," Boston forward Jared Sullinger (11 points, four rebounds) said.

While the Grizzlies dominated most of the last two quarters, the Celtics had a chance to tie when Memphis forward Jeff Green made a bad inbounds pass with 3.9 seconds left in the game. Boston guard Avery Bradley (14 points) missed a 3-point attempt and then point guard Isaiah Thomas, who carried the Celtics with 35 points and eight assists, made a 3-pointer, but it was after the buzzer.

Memphis (21-18) won its sixth straight home game.

"Six?" Grizzlies center Marc Gasol said. "It was a hard six."

Boston (19-18) lost its third straight game.

The Celtics stretched a 15-point halftime lead to 61-40 with 10:05 left in the third quarter after a 3-pointer from forward Amir Johnson (14 points, nine rebounds). Memphis, however, made an 18-2 run and Boston carried a 76-68 advantage into the fourth quarter.

From there, the Grizzlies got their first second-half lead at 86-85 with 3:49 left in the fourth quarter on a driving hook shot by Gasol (11 points on 5-of-17 shooting from the field, 11 rebounds).

The teams traded the lead several times in the last four minutes, but a putback from forward Matt Barnes (12 points, nine rebounds) with 50.5 seconds left gave Memphis a 93-92 edge and the Grizzlies never trailed again.

The Celtics shot 42 percent from the floor (37 of 88) and hit 31.8 percent from 3-point range (7 of 22). Memphis shot 36.9 percent from the field (31 of 84) and 25 percent from beyond the arc (4 of 16).

The Grizzlies had a huge 58-39 rebounding edge.

"They had 15 offensive rebounds in the second half," Boston coach Brad Stevens said. "We didn't score enough to keep them at bay."

Point guard Mario Chalmers had 18 points for Memphis and guard Tony Allen added 15 points and 10 rebounds.

Memphis won despite having 12 assists to 21 turnovers that led to 25 Boston points. Part of that was a function of not having starting point guard Mike Conley (left Achilles injury).

Chalmers played more than 32 minutes. When Joerger wasn't comfortable with what he got from 10-day-contract guard Elliot Williams, who played less than five minutes, he spread point guard duties among Allen, Green and Vince Carter (eight points, three blocks) when they were playing together.

Meantime, Randolph is adjusting to his role off the bench well enough to joke about it.

"I just said messed with Marc and said, 'Should I go for the Sixth Man of the Year Award?'" Randolph said.

NOTES: When Lionel Hollins was not retained by the Grizzlies after taking them to the 2013 Western Conference Finals, assistant Dave Joerger was promoted to head coach. On Sunday, Joerger responded to the news of Hollins being fired by the Brooklyn Nets (10-27, second-worst record in the NBA). "We care about him deeply and tried to reach out to him," Joerger said, adding, "He's a fighter. He'll go out and do it the way he thinks is best to do it and won't apologize for it." ... Celtics G Avery Bradley moved into the starting lineup after missing three straight games with a sore left hip. Bradley was Boston's second-leading scorer with 14.7 points per game. ... Memphis G Mike Conley missed his third straight game (left Achilles) and G Courtney Lee missed his second consecutive game (left hip). ... The Celtics ranked second in the league in steals at 9.39 per game.