MEMPHIS, Tenn. -- When JaMychal Green's putback dunk with 0.3 of a second left in the fourth quarter gave the Memphis Grizzlies a two-point lead, Dallas Mavericks forward Harrison Barnes thought they were done.

Although the Grizzlies had rallied from a 17-point halftime deficit, seized the lead late in the third quarter and stretched to it as many as seven points in the fourth quarter, Barnes worried they were going to come up short.

But after an official review confirmed Green's basket was good, 0.2 also went back on the game clock.

"That changed it," Barnes said. "Now we can actually get a shot up."

Barnes turned out to be the guy that got that shot up beyond the arc. The ball went down, beating the buzzer and giving the Mavericks a 95-94 victory on Wednesday night at FedExForum and sending the Grizzlies to their sixth straight defeat.

Barnes, who led the Mavericks with 22 points and nine rebounds, didn't even try to play it off as a sure thing -- that he knew it was going to be good.

"Guys say that," he said, "but I had no idea. That was prayer answered."

The Mavericks (4-15) have won half their games at the expense of the Grizzlies. And Memphis (7-10) has not won at FedExForum since Oct. 28 against Houston.

"He threw up a 30-foot bank shot to break our heart,"

said Memphis coach David Fizdale. "But hey, this is the league. When you take punches, you take them, you get back to work."

Dallas trailed 56-39 halftime but took a 72-70 lead with 47 seconds left in the third quarter on a driving layup from guard Devin Harris (11 points, four steals.). The Mavericks led 74-72 to start the fourth quarter.

"We lost focus defensively," said Green, who finished with eight points and nine rebounds. "They had a 35-point (third) quarter. That's something that can't happen."

Memphis forward Chandler Parsons (11 points) said, "We had that game in the first half. And the way we played in the third quarter allowed it to even get there. So we can blame refs, basketball gods, whoever we want, but we simply didn't play 48 minutes and allowed them to put themselves in that situation and make a lucky shot at the buzzer."

Luck might have been involved in the game's last shot, but Dallas coach Rick Carlisle didn't see anything lucky about what his team did after halftime.

"We came out of the locker room angry and determined," he said. "Even when they got that go-ahead basket at the end, everyone kept believing. Very positive last timeout. I haven't been this happy for a group of guys in a long time. These guys deserve this win. It was fought hard."

Guard Dennis Smith Jr., who finished with 17 points, gave the Mavs a lift in the third quarter with 11 points and hit 3 of 4 3-point shots in the quarter.

"It really sparked everybody," Carlisle said.

Guard Tyreke Evans paced Memphis with 18 points, nine rebounds and seven assists (six turnovers) off the bench. Center Marc Gasol finished with 14 points, 10 rebounds and four assists. Rookie center Deyonta Davis had a season-high 14 points and seven rebounds off the bench.

The Mavericks shot 42.9 percent from the floor and went 9 of 28 from 3-point range for 32.1 percent. Memphis shot 45.7 percent from the field while going 7 of 29 from distance for 24.1 percent.

Dallas forward Dirk Nowitzki finished with 13 points and eight rebounds. Guard J.J. Barea had 11 assists with 10 points off the bench.

Memphis got 13 points from rookie Dillon Brooks.

Barnes had missed a potential game-winning shot at the end of regulation Monday against Boston and then the Celtics won the game in overtime.

"Great pros have tunnel vision, a short memory," Carlisle said. "That's the biggest shot we've had in quite some time."

NOTES: The Mavericks and Grizzlies entered the game with the same record (2-8) in their previous 10 games. ... F Dirk Nowitzki now has 1,225 career blocks and needs 26 to pass Shawn Bradley (1,250) for first-place on the Mavericks' all-time list. ... Memphis G Tyreke Evans has seven games of 20 or more points off the bench this season and leads the NBA in points scored as a reserve. ... Asked the best way to handle losing a key player during the season, Dallas coach Rick Carlisle said, "You do what (the Grizzlies) are doing and throw it to (Marc) Gasol every time, and let him dictate the game. Look, there are no other Mike Conleys walking around on the street." Conley is out indefinitely with a left Achilles injury.