MONTREAL (AP) -- Tampa Bay's Nikita Kucherov scored a contentious goal at 2:06 of the second overtime to give the Lightning a 2-1 victory at Montreal on Friday in the opening game of their NHL Eastern Conference semifinal series.
It was also close in the opener of the Western Conference semifinal between Chicago and Minnesota, with the Blackhawks snatching victory after having given up a three-goal lead.
Kucherov scored the winning goal on a play that replays clearly showed was offside.
"It's really frustrating, losing a game on an offside," Montreal coach Michel Therrien said. "Those things are not supposed to happen.
"It's not like a penalty. It's not a judgment call. It's black or white. It was clearly offside and we ended up losing the game."
Game 2 of the best-of-seven series is Sunday in Montreal.
The Lightning were outshot 44-35 and got some breaks when Montreal's David Desharnais and Max Pacioretty both hit the post early to the relief of Tampa Bay goaltender Ben Bishop, who was keeping the result in perspective.
"It's nice, but it doesn't mean much," Bishop said about the victory. "We just came off a series (against Detroit) where we lost the first game. "It's nice to win the first game but now we have to forget about it and get ready for the next one."
Tyler Johnson scored his NHL-leading seventh of the playoffs for Tampa Bay in the third period only to see Pacioretty tie it with 5:13 left.
Replays showed the Lightning were offside on the play that led to the winner, but it took 12 seconds from then until Kucherov scored, plenty of time to get the puck out of the zone.
But defenseman Greg Pateryn coughed up the puck in a corner and Valtteri Filppula fed Kucherov in the slot for a quick wrist shot past Carey Price.
"Boyle made a good play and Filppula got it through the D's legs," Kucherov said. "He put it right in my wheelhouse. I just had to shoot."
Chicago's Teuvo Teravainen broke a tie with his first playoff goal, giving the Blackhawks a 4-3 win against Minnesota.
The Blackhawks, trying to knock out Minnesota for the third straight year, will also host Game 2 on Sunday.
The 20-year-old Teravainen came through with 58.2 seconds left in the second period after Chicago blew a 3-0 lead. Held out of the final four games of the first round, he scored from a difficult angle.
Brandon Saad scored 1:15 into the game. Patrick Kane and Marcus Kruger added goals just over 2 minutes apart in the first period. Corey Crawford made 30 saves for the Blackhawks.
Zach Parise had a goal and an assist for Minnesota, Jason Zucker and Mikael Granlund also scored, and Thomas Vanek had two assists. Devan Dubnyk stopped 31 shots.