CALGARY -- Johnny Gaudreau doesn't mind putting in a little extra work.
Gaudreau scored with 1:40 remaining in overtime to complete his second NHL hat trick and give the Calgary Flames a 5-4 win against the Boston Bruins at Scotiabank Saddledome on Friday.
Gaudreau leads the NHL with three goals and five points in the first season of 3-on-3 overtime.
"Last year I was fortunate enough to get a hat trick, but it was in a different arena," said Gaudreau, who scored three goals against the Los Angeles Kings on Dec. 22, 2014. "I was fortunate to get one tonight. It's always exciting seeing hats get thrown on the ice, whether it's your own hat trick or someone else's hat trick. It was a great team win for us."
Gaudreau was set up by former Bruins defenseman Dougie Hamilton on the game-winner. Hamilton spotted Gaudreau, who trailed the play, in the high slot; Gaudreau skated in and beat Bruins goaltender Tuukka Rask with a deke.
"I think our team likes 3-on-3 overtime," Gaudreau said after the Flames improved to 6-1 in OT. "We do pretty well with it. We have a lot of great guys on our team that can play 3-on-3 in a lot of different positions. Dougie made a great play there at the end and I had a semi-breakaway and found a way to put it in the net."
Coach Bob Hartley said Gaudreau has heightened expectations in overtime.
"Outstanding performance," Hartley said. "Johnny was one more time on top of his game. It's funny. On the bench, even the players were telling 'Go Johnny, get another one.' Really, I have the same feeling. When Dougie gave him that pass through the middle and I saw him alone I knew it was in. He's so clutch. He comes up with big plays, big goals. He's an unbelievable performer."
Mark Giordano and Jiri Hudler scored for Calgary (10-14-2), which has won six consecutive games at home.
Hudler tied the game with 1.2 seconds remaining in the third period when he put a loose puck in the crease over the goal line. Boston coach Claude Julien used his challenge, contending that Rask had been interfered with, but the goal stood. It was Hudler's first since Oct. 30.
"It's disappointing losing a game like that," Bruins forward Brad Marchand said. "We're one second away from a win. That's how it goes sometimes."
Marchand had two goals, and Zdeno Chara and Matt Beleskey scored for Boston (13-8-3). The Bruins have lost two straight; their five-game winning streak ended with a 3-2 shootout loss to the Edmonton Oilers on Wednesday.
"We all enjoy being in games like that," Marchand said. "That's not the type of game we normally play in and we can't continue to play in games like that. We're not a run-and-gun-type team. We have to battle it out a little more down low. It was definitely a very exciting game."
Boston ends its three-game Western Canada trip against the Vancouver Canucks on Saturday.
"Four out of six points on a road trip is still a very good road trip, very successful," Marchand said. "We want to make sure we bounce back and have a big one tomorrow."
Hamilton's setup on Gaudreau's game-winner atoned for an error that allowed the Bruins to go ahead 4-3 with 1:06 left in the third. On a power play, the puck skipped over Hamilton's stick at the Boston blue line, forcing him to knock Marchand's stick out of his hands on the breakaway. Marchand scored on the shorthanded penalty shot.
"I think the whole play, bouncing puck goes right by me and he's cheating for it," Hamilton said. "At that point you don't really know what to do. I tried to make a play on him early rather than let him skate in and I think it's unfortunate that it knocked the stick out of his hands. I don't know what would've happened if I just hit his hands. It is what it is.
"I'm thankful we tied it up there and ended up winning. Probably one of the crazier games I've ever been a part of and definitely a weird one playing against my old team."
Gaudreau scored on Calgary's first shot 33 seconds into the game. Flames forward David Jones picked up a turnover from Chara at the blue line and passed to Gaudreau, who beat starting goalie Jonas Gustavsson through the five-hole.
Giordano put the Flames up 2-0 at 15:55, taking a pass from TJ Brodie before beating Gustavsson short side with a wrist shot from the faceoff circle.
Beleskey tipped Chara's point shot past Ramo with 2:41 remaining in the first to cut Calgary's lead to 2-1. Beleskey, who signed with Boston in July, scored in all five games of a 2015 Western Conference Second Round series to help the Anaheim Ducks eliminate Calgary.
The Flames and Bruins traded three quick goals to start the second period.
Marchand tied the game 2-2 by snapping a shot over the glove of Ramo at 1:36 for his team-leading 11th goal of the season.
Gaudreau scored his second of the game 20 seconds later, taking a pass from Hudler from below the goal line and tucking the puck past Gustavsson's outstretched pad and over the goal line.
Bruins coach Claude Julien replaced Gustavsson with Rask after Gustavsson allowed three goals on 11 shots.
Chara's slap shot through traffic beat Ramo at 2:22 to tie the game 3-3.
Flames defenseman Kris Russell did not play because of an upper-body injury; he is day-to-day. Jones left the game in the first period and did not return because of a lower-body injury.
Hamilton was traded by the Bruins to the Flames this offseason and then signed a six-year contract with Calgary.