MONTREAL - After a fairly quiet regular season, digger Tom Kostopoulosis making noise in the playoffs for the Montreal Canadiens.

The checking winger scored 48 seconds into overtime to give the Canadiens a comeback 4-3 victory over the Philadelphia Flyers in the opening game of their NHL playoff series on Thursday night.

Montreal leads the best-of-seven Eastern Conference semifinal 1-0 with Game 2 set for Saturday night at the Bell Centre.

''It's exciting,'' said Kostopoulos, the surprise source of three post-season goals thus far. ''It's unbelievable how we came back twice to tie it up.''

Alex Kovalev scored his second goal of the game with 29 seconds left in regulation - on a power play and with goalie Carey Price pulled for an extra attacker - to tie the score 3-3 and force overtime.

In the extra period, defenceman Andrei Markov kept the puck in at the blue-line and put a low shot on goal. Kostopoulos beat Martin Biron on his second whack at the puck from the edge of the crease.

''Hard work by my linemates created the turnover and Markov made a good play to get the puck on net,'' added Kostopoulos, who is in the playoffs for the first time in his six-year NHL career. ''Biron made a good save on the first shot and I was lucky to get the rebound.''

R.J. Umberger and Jim Dowd scored in the first period for the Flyers, while Andrei Kostitsyn and Kovalev tied it up with goals in the second for Montreal.

The Flyers weren't happy with a kneeing penalty called on centre Mike Richards for bringing down Kovalev with 1:09 left to play, which gave Montreal the chance to tie the game.

And they weren't thrilled to see a video review go against them when Kovalev batted a puck out of the air to score in the second period, although replays appeared to show his stick blade was just below the crossbar, or at least close enough to make it difficult to overturn the officials' call of a goal...