Chris Gratton and Doug Gilmour scored first-period goals and Hasek stopped 31 shots as the Sabres edged the Philadelphia Flyers, 2-1, to take Game One of their best-of-seven Eastern Conference quarterfinals series.
Buffalo had scored just two goals in losing all four regular-season meetings with Philadelphia, including Sunday's 2-1 defeat. That game gave the Flyers the home-ice advantage in this series, but Hasek, who stopped a penalty shot by Mark Recchi, and the Sabres took it away on Wednesday.
"It's different now," Philadelphia left wing John LeClair said. "It's a seven-game series. Those four games didn't mean much to us. We weren't looking at them like we own them or anything like that. We were prepared. We weren't taking them lightly by any means."
Hasek stopped 13 of Philadelphia's 14 shots in the opening period and made 18 saves over the final 40 minutes. With Buffalo holding a 1-0 lead, the five-time Vezina Trophy winner stopped Recchi's penalty shot with 8:19 left in the opening period.
"I know from my experience that we have faced extremely tough goaltenders in the previous three years I have been here," Buffalo coach Lindy Ruff said. "I think you just throw pucks at the net. I didn't think there was any scheme that we won, we got as many chances as we could."
Sabres defenseman James Patrick was called for closing his glove on the puck in the crease to give the Flyers a penalty shot against the Sabres in the playoffs for the second straight year. Recchi faked a shot in an effort to get Hasek to go down, but the goalie stacked his pads and knocked the puck away with his glove.
"I was trying to catch my breath first. My mind set was to try and get him to go down and then get it up and over him," Recchi said. "I just didn't get it high enough, he made a good save."
Hasek also stopped a penalty shot by Eric Desjardins last April 16 in Philadelphia's 2-0 win at Buffalo. The Flyers defeated the Sabres in five games in the quarterfinals last season.
Buffalo, which did not have a lead against Philadelphia in any of the four games this season, went ahead when Gratton scored at 4:09 of the first.
Gratton took a pass from Steve Heinze and took a wrist shot from the right faceoff circle that went off goatender Roman Cechmanek's glove and into the net. It was Gratton's first playoff goal since 1998 when was with Philadelphia.
"We watched video on Cechmanek," Gratton noted. "He tends to come out and cut down the angles. I was trying to get his feet moving a little bit. I shot it and fortunately it went in."
Desjardins tied it with six minutes left in the first. Paul Ranheim skated into the Buffalo zone before losing control of the puck in the slot. Desjardins alertly got to the puck at the edge of the right circle and flipped a wrist shot by Hasek's left shoulder for his 20th career playoff goal.
Gilmour, who is expected to retire at the end of the playoffs, got the game-winning goal with 1:56 to go in the first. Cechmanek stopped a shot from the left point, but Gilmour put the rebound in on his second attempt from the top of the crease.
"Cechmanek made the save on Audette's shot," Gilmour said. "It hit my skate and went into his pads. I got the rebound and I put it through him. You're in the opposition's building, you have to go out and create as many chances as you can. You know you're not going to get a lot of chances in here. If they make a mistake, you have to capitalize."
The Sabres killed all three of Philadelphia's power-plays, including a four-minute span in the second period when Miroslav Satan received a double-minor for high sticking.
Of Hasek's eight saves in the second period, his best came with eight minutes to go when he turned away Simon Gagne's drive from the left circle.
"They played a pretty good game. They bottled us up pretty good through the neutral zone," Recchi said. "I don't think we saw either team's best game. Obviously they get a 2-1 lead, they were able to hold on. Our power play has to be better. That's something we'll have to look at the next couple of days."
Buffalo's defense contained the Flyers in the third period and Hasek did not have to make any of his typical acrobatic saves in stopping 10 shots.
Cechmanek went to the bench for an extra attacker with just over a minute remaining. Gagne drove to the net with 56 seconds left, but slid the puck across the crease. The Flyers kept control of the puck and Desjardins fired a slap shot six seconds later that Hasek stopped. Buffalo sent the puck into the Philadelphia zone and did not allow the Flyers to threaten the rest of the way.
Cechmanek, who backed up Hasek for the Czech Republic team that won the gold medal in the 1998 Olympics, finished with 24 saves in his first playoff game.