Radek Martinek rarely been the offensive star during 11 NHL seasons, so the chance to savor a winning goal was meaningful to the 36-year-old defenseman.

Martinek, injured most of last season, scored the tiebreaker eight minutes into the third period as the Islanders handed the Canadiens their first regulation loss in nearly a month with a 6-3 victory last night.

The quiet Martinek, who had not scored since Oct. 12, 2011, when he was with Columbus, was all smiles as he gave credit to teammates.

“It feels very good to win two straight at home after the struggles we’ve had,” he said, referring to the Islanders winning just twice in their first 11 home games. “Now we have something to build on.”

Martinek’s shot from the left point on a pass from Kyle Okposo eluded goaltender Carey Price at 7:56. John Tavares scored his team-leading 14th goal with 1:07 left before Colin McDonald closed the scoring with an empty-netter.

Brian Gionta’s power-play goal at 6:07 of the third — the 20,000th goal for the Canadiens since the NHL was formed in 1917 — had tied the game at 3.

“This was a tough one for us,” Gionta said. “They are a dangerous offensive team and they have the power when they play their game. We simply didn’t play the way we wanted to play.”