Boston goaltender Linus Ullmark drops to the ice as Florida’s Matthew Tkachuk skates past before scoring the winning goal in overtime Wednesday night in Boston. Charles Krupa/Associated Press

BOSTON — Matthew Tkachuk scored six minutes into overtime to help the Panthers beat the Boston Bruins 4-3 on Wednesday night and force their first-round playoff series back to Florida for a sixth game.

One game after Bruins goalie Linus Ullmark tried to fight Tkachuk, the Panthers’ forward took advantage of Ullmark’s sloppy puck play behind the net and cut the Presidents’ Trophy winners’ lead in the best-of-seven series to 3-2.

Sergei Bobrovsky made 44 saves for Florida, which has won back-to-back games in Boston but lost twice at home. Anthony Duclair, Sam Bennett and Sam Reinhart also scored — each one giving the Panthers a lead.

Patrice Bergeron scored in his return from an injury, and Ullmark stopped 21 shots for the Bruins. Brad Marchand and Taylor Hall had the other goals for Boston, which rallied from 1-0, 2-1 and 3-2 deficits to force overtime.

It was 2-1 Florida when Bergeron tied it five seconds into a Boston power play, tipping Marchand’s shot into the net. Seconds later, Tkachuk drew a hooking penalty on Jakub Lauko, and Reinhart quickly put the Panthers back in front.

With about 10 minutes left in regulation, though, Hall fought for a puck in the slot, turned and wristed it into the net to tie the game 3-3. The Panthers earned a faceoff in the Boston zone with 8 seconds left, but Marchand poked the puck free and chased it down, breaking free down the ice.

Bobrovsky turned him aside with 1 second left on the clock.