MILWAUKEE -- When Milwaukee Bucks coach Jason Kidd announced before their game Tuesday night against Boston that center Greg Monroe would come off the bench for the first time this season, it came as something of a shock to the assembled reporters.

Monroe, though, wasn't remotely surprised.

"We'd been practicing like that the last few days," Monroe said. "You guys didn't know about it, but I knew."

Kidd made the move with the hopes of snapping the team out of a season-high five-game losing streak and it paid off as Monroe responded in a big way, scoring a season-high 29 points with 12 rebounds as the Bucks held off the Celtics in the final seconds for a 112-111 victory.

"He was the sixth man of the year tonight," Kidd said. "That kind of line would make him an All-Star and the front-runner for sixth man of the year.

"It's not easy when you've started your whole career then you're asked to do something different. But you take your hat off to him for being a pro; he did his job at a very high level tonight."

Monroe scored 12 points in the third as Milwaukee erased a one-point halftime deficit with a season-high 40 point quarter to go up 93-74 heading into the fourth. The Celtics, who had won four straight and nine of their last 10, stormed back in the fourth and finally tied the game at 109 on Jae Crowder's 3-pointer with 23.9 seconds to play.

Monroe appeared to put the Bucks ahead for good, sinking a one-foot hook shot with 1.9 seconds left but after a Boston timeout, Bucks guard Jerryd Bayless was called for a foul on Kelly Olynyk, who tied the game at 111 with one second remaining.

"You just have to chip away and make it a game within a game," said Crowder, who along with Avery Bradley scored 18 to lead Boston. "Once we got it down to 10, it was a game."

Kidd called a timeout and Milwaukee was set to inbound the ball in front of its bench. Forward Giannis Antetokounmpo found shooting guard Khris Middleton, who was looking to get the ball back to Monroe but drew the foul from Bradley and went to the line for the game-winner.

"It's a good win for us," said Middleton, who scored 18 of his 20 points in the second half. "We've been struggling on the road, so coming back home and getting a win, we needed it."

Monroe wasn't the only Bucks starter to come off the bench Tuesday. Point guard Michael Carter-Williams, who's bounced back and forth between the two units this season, also watched the opening tip from the bench, but finished with 16 points, six rebounds and five assists.

"We just wanted to see something different," Kidd said. "Michael and (Monroe) coming off the bench, they were big."

O.J. Mayo started at point in place of Carter-Williams while Mason Plumlee got the nod at center but the lineup switch didn't last long. Mayo missed a pair of 3-pointers and collected two fouls before going to the bench with 9:02 left in the opening quarter.

Monroe wasn't far behind, taking over for Plumlee at the 7:33 mark, but he went 2 for 6 from the field was largely ineffective as the Bucks fell behind by 10 before cutting the deficit to 30-26 heading into the second.

Rashad Vaughn's 3-pointer put Milwaukee up 49-46 with 4:45 left in the half and Monroe took over in the quarter hitting 5 of 8 shots to score 11 in the second.

Boston struggled to contain Monroe but also battled its own inability to protect the ball; the Celtics turned it over 18 times for 25 Milwaukee points, including 14 points off eight turnovers in the fourth.

"We really didn't move the ball at the end of the third quarter," Boston coach Brad Stevens said. "That was as impactful as Monroe going off; we turned it over and we took tough shots so we were lucky to be in the game at the end."

NOTES: The game marked the return for Bucks SG O.J. Mayo, who hadn't played since suffering injuring his left hamstring. ... Boston F Jae Crowder was available and in the starting lineup Tuesday despite playing a sprained right ankle for the last two games.