Tampa Bay’s 41-year-old goaltender Dwayne Roloson shut out the Pittsburgh Penguins to preserve a 1-0 victory for the Lightning, while the Bruins seized a 4-3 overtime win over the Montreal Canadiens on Nathan Horton’s series-clinching goal.

Horton delivered the slap shot at 5:43 in the overtime as the Bruins celebrated the 4-3 best-of-seven series win over their Northeast Division rival.

“(Montreal’s Carey Price) is such a great goaltender, and you know you’re not going to beat him clean,” Horton told reporters. “You try to get rebounds, and at the end I got a deflection that went in.

“It feels great. This is exactly how we wanted it. It was a tough battle, they are a great team and we really had to give our best.”

Boston had trailed 2-0 in the series but stormed back to win four of the next five games to advance to a showdown with the Philadelphia Flyers for a second successive year.

The Flyers shocked the Bruins in 2010 when they rallied from a 3-0 series deficit to win the best-of-seven series.

On Wednesday, the Canadiens fought back from a 2-0 deficit in the first period and forced the extra session with just 1:57 left in regulation when P.K. Subban drilled a slap shot past goaltender Tim Thomas.

Thomas recovered with five of his 34 saves in the overtime.

Johnny Boychuk and Mark Recchi gave Boston the early 2-0 lead in the first where Montreal’s Yannick Weber made a wrist shot to cut the lead to 2-1.

Tomas Plekanec tied the game for the Canadiens in the second before Chris Kelly’s backhand at 9:44 in the third put the home team back ahead 3-2.

Price made 30 saves for the Canadiens.

In Pittsburgh, Roloson finished with 36 saves and Sean Bergenheim scored the game’s only goal to give Tampa Bay the 4-3 series victory — their first series win since 2004 — and a second round clash with the top-seeded Washington Capitals.

Pittsburgh, playing the post-season without injured forward Sidney Crosby and Evgeni Malkin, pushed until the very end.

The Penguins received a power-play in the final 1:33 of the game, after Tampa Bay’s Nate Thompson was called for slashing, but could not equalize.

Netminder Marc-Andre Fleury had 22 saves in the defeat.