MEMPHIS, Tenn. -- For three quarters, the Memphis Grizzlies were out of sync and appeared to be just going through the motions.

But a fourth-quarter rally fueled by a more energetic defense allowed Memphis to overcome its lethargic performance for an 84-78 victory over the Cleveland Cavaliers on Monday night.

"We knew coming into this game that it was going to be a tough game," said Memphis forward Zach Randolph, who finished with 19 points. "The guys didn't play too well. It was a fight to the end."

Marc Gasol matched Randolph with 19 points for the Grizzlies. Rudy Gay added 15 points and Quincy Pondexter had 10, including 2-of-3 shooting from outside the arc, as NBA-leading Memphis (10-2) won its second straight.

Memphis played without starting point guard Mike Conley, who sat out with flu-like symptoms, and his absence was evident within the offense. Jerryd Bayless started in Conley's place, scoring nine points with six assists, while committing three turnovers. The lack of consistency resulted in only 16 assists and a season-low in points for Memphis, which entered the game averaging 100.7 points.

"It wasn't tough. It was just different," Bayless said of the starting role. "I don't play with (the starters) ever. I always play with (the reserves). It's a much different setting. I've never really practiced with them either, so it was different trying to get used to that. We won, and that's all that matters."

Anderson Varejao had 15 points and 22 rebounds -- including eight on the offensive glass -- and Dion Waiters also scored 15 to lead Cleveland. Daniel Gibson added 11 points for the Cavs, who lost their third straight and ninth in their last 10 games.

The Cavaliers still held a six-point lead with 8:28 left, but Memphis closed the game on a 16-4 run. The Grizzlies outscored Cleveland 22-9 in the fourth quarter.

"We took some bad shots," Varejao said. "We only shot 20 percent, I believe, in the fourth quarter. It was just bad decisions, and then we had to find a way back into the game.

"We are playing as good as them for the whole game, and the last 2 or 3 minutes are where we are losing."

Cleveland had a 41-33 advantage on the boards, while Memphis outscored the Cavs 44-38 in the paint.

The Memphis offense was sporadic at best through the first three quarters, leading to Cleveland holding a seven-point lead at that point. But Memphis opened the final frame with a 12-5 run, tying it at 74 on back-to-back 3-pointers from Pondexter and Gay.

Cleveland wouldn't surrender the lead until Tony Allen hit a pair of free throws with 2:49 left to give Memphis a 78-76 lead.

Randolph's inside basket with 1:29 to play extended the margin to 80-76, but a rebound dunk by Alonzo Gee with 44.5 seconds left cut the lead to 80-78. Cleveland got no closer as Bayless, who was only 3 of 11 from the field on the night, hit a jumper with 24 seconds left then converted two free throws for the final score.

"I believe in myself and I got a good look, so I let it fly," Bayless said of the jumper. "I shot terrible. I didn't play well, and honestly it wasn't me, it was the guys who really picked us back up. It was my fault we got in the hole, and I've just got to play better."

Cleveland used 50 percent shooting and a much more spirited approach than the Grizzlies to take a 47-42 lead at the half. Varejao had 11 points and 12 rebounds at the break.

"He's got a motor," Randolph said of Varejao. "He's non-stop movement. He reminds me of myself a couple of years ago. You've got to give him a lot of credit. He works hard. He's non-stop."

Randolph already had 13 points at the half, and Gasol and Gay had 10 apiece.

While both teams committed eight turnovers before the break, Memphis seemed to be sleepwalking through the motions.

"We should have played better," Gasol said. "We played their game, and we shouldn't have done that."

Memphis came out in the second half and still appeared sloppy, allowing Cavs to build the lead to 10, their biggest of the game. Varejao was getting on the boards, and Cleveland continued shooting at a 50-percent clip in the third.

Allen and Gasol were providing the only energy for Memphis at the midway point of the third quarter as Cleveland maintained a lead of about five points.

Varejao's jumper as the horn sounded at the end of the third gave Cleveland a 69-62 lead entering the fourth -- the first time this season Memphis has trailed at the end of three.

But Memphis clamped down the defense with Allen guarding Waiters and holding the Cavaliers' second-leading scorer scoreless in the fourth, part of Memphis limiting Cleveland to a 4 for 20 shooting touch in the fourth, including misfiring on nine of 10 from outside the arc.

"As I told our guys, we just have got to keep competing like this," Cleveland coach Byron Scott said. "Sooner or later being in this situation this many times, we will find a way to break through it."

Game notes
Memphis caused 18 turnovers, the 116th consecutive game where the Grizzlies have forced at least 10 -- the longest such streak in the NBA. ... Jeremy Pargo, who played for Memphis last season, is starting at guard for Cleveland with Kyrie Irving out because of a left index finger injury. Pargo finished with nine points. ... It was Varejao's ninth double-double of the season. His 22 rebounds were one short of his career high set earlier this season against Washington. ... Randolph ended the night with eight rebounds, marking the first time this season he hasn't recorded a double-double.