DENVER -- Tyler Bozak's return to Denver was the end of the Colorado Avalanche's longest winning streak in two seasons.

Bozak had a hat trick in the third period, and the Toronto Maple Leafs broke open a tie game with four goals in the last 20 minutes to beat the Avalanche 7-4 Monday night.

Center Leo Komarov had two goals and an assist, and left winger James van Riemsdyk added a goal and two assists for Toronto (12-13-7). Defenseman Jake Gardiner had four assists.

Bozak spent his two-year collegiate career not far from Pepsi Center. The center had 26 goals and 31 assists in 60 games for the University of Denver from 2007-09 before signing as an undrafted free agent with Toronto.

He has returned to Colorado before with the Maple Leafs but never with this much success. He didn't complain when the Avalanche fans didn't toss hats on the ice after his third goal.

"I had a couple buddies here so I thought they might have thrown it out there, but that's OK," he said. "They might not have been close enough to the ice. I didn't expect hats there."

Maple Leafs left winger Joffrey Lupul also scored, and goaltender Jonathan Bernier stopped 24 shots for Toronto, which scored three times on the power play.

Bozak got his first goal on a two-on-one rush with van Riemsdyk 49 seconds into the third. He scored on a breakaway at 6:47 to put Toronto ahead 5-3, and van Riemsdyk made it a three-goal game with his 11th goal at 10:40.

Bozak finished the hat trick with an empty-net goal at 16:20.

"We were tied going into the third and whenever you are on the road and go into the third tied, it's not bad," Bozak said. "We got some good plays and some lucky bounces."

The Avalanche got two goals from right winger Jack Skille. Defenseman Erik Johnson and center John Mitchell also scored for Colorado, which had its five-game winning streak stopped.

"Tough way to go into the break," Avalanche center Nathan MacKinnon said. "We've been playing some good hockey. When you give up three power-play goals it's tough to win."

Goalie Semyon Varlamov was in net for all five wins and rode a personal six-game winning streak into Monday. He had a 0.99 goals-against average during the streak, but he allowed six goals on 21 shots Monday.

Coach Patrick Roy said he didn't pull Varlamov because his backup, Reto Berra, suffered an ankle injury playing soccer before the game. He is scheduled to have an MRI on Tuesday.

Roy also said defenseman Nate Guenin, who left the game in the second period with a head injury, has a possible concussion.

The Avalanche (17-17-1) went ahead 1-0 on Skille's goal 2:27 into the game. It was his fifth of the season and second in as many games.

Colorado had a chance to add to its lead on a power play midway through the first but couldn't get a shot on goal. The Maple Leafs cashed in when they got their chances with the man advantage.

Komarov tied the game at 13:34 of the first when his shot from the right circle beat Varlamov high on the short side. Toronto took a 2-1 lead 4:08 later when Lupul scored his ninth of the season on the power play.

Colorado tied it 1:07 into the second period on Mitchell's eighth goal.

Komarov got his second goal of the night and 15th of the season when he scored seven seconds into right winger Alex Tanguay's holding penalty at 12:03 of the second to make it 3-2.

The Maple Leafs, who were 4-for-5 on the power play when they beat Colorado on Nov. 17, finished 7-for-8 against them for the season.

"They just have our number; there's no other way to put it," Mitchell said. "It's disappointing because the penalty kill has been good of late and they come in, three power plays, three goals. It's a tough pill to swallow."

Johnson tied it at 18:43 of the second with a power-play goal. It was Colorado's first shot on three power-play opportunities.

NOTES: Avalanche G Semyon Varlamov was named the NHL's First Star of the Week after going 3-0-0 with a 0.67 goals-against average, .981 save percentage and one shutout as Colorado extended its winning streak to five. ... Toronto G Garret Sparks was out for the second straight game with a lower-body injury. ... With the team playing well, Colorado coach Patrick Roy stuck with the same lineup against the Maple Leafs. D Brandon Gormley and RW Chris Wagner were the healthy scratches. ... Toronto G James Reimer worked out on the ice Monday and could be available Sunday when the Maple Leafs play the New York Islanders. He has missed five consecutive games.