Brad Marchand scored a backhand game-winning goal with 20 seconds remaining in overtime as the Boston Bruins defeated the visiting Calgary Flames 4-3 on Thursday.

After Elias Lindholm forced a turnover behind the net, Marchand followed his own initial shot that Calgary goaltender Dustin Wolf saved and put the rebound back through the crease for the deciding goal.

Marchand has 21 overtime goals, one behind Sidney Crosby for second place and five back of all-time leader Alex Ovechkin.

Prior to an up-and-down overtime, Calgary scored two third-period goals to force overtime after Boston’s two-goal outburst in a 31-second span in the second broke a 1-1 tie.

Pavel Zacha registered one goal and one assist, including his 300th career point, to lead the Boston offense in regulation.

Hampus Lindholm and Cole Koepke also scored for the Bruins, who have won three of four. David Pastrnak dished out two helpers.

Boston’s Joonas Korpisalo made 34 saves.

Tyson Barrie, Yegor Sharangovich and Nazem Kadri scored Calgary’s goals.

Wolf stopped 34 shots as the Flames were unable to post consecutive overtime wins.

Boston had a 38-39 shots advantage, including 5-4 in the extra session.

A power-play goal 58 seconds into the third brought Calgary within 3-2. Stationed in the slot, Sharangovich made a deflection on a MacKenzie Weegar shot from the top of the point that sailed through heavy traffic.

Kadri sniped home the tying goal at 9:55, making a toe-drag move in the left circle and using Boston defenseman Nikita Zadorov as a screen to beat Korpisalo top-corner.

Hampus Lindholm needed only 2:04 of the first period to open the scoring for Boston, taking a feed from Pastrnak in the right circle and sliding from left into the slot to pot a backhand shot into a virtually open net.

The visitors found a game-tying response 19 seconds later when Ryan Lomberg settled the puck off Justin Kirkland’s faceoff win and ripped a hard shot from the point that eluded Korpisalo for his first goal as a Flame.

The Bruins took command with two quick-fire goals in the second, beginning with Zacha’s first five-on-five goal of the season at 8:25. Pastrnak slid down the wing and sent a return pass back to Zacha, who teed up the go-ahead goal high on Wolf.

Koepke continued his hot start in Boston at 8:56, redirecting Charlie Coyle’s pass from the end line into an open side of the net on the left to make it 3-1 Boston.