MONTREAL -- Feeling fortunate to be trailing the Pittsburgh Penguins by only one goal through two periods of Game 4, the Montreal Canadiens wasted no time taking full advantage of their final 20 minutes.
Lapierre drew the Canadiens even at 2 with a wraparound goal 2:20 into the third.
"We knew in that second intermission that we probably had played our worst two periods of the playoffs," said Gionta, who put Montreal ahead with his fifth goal at 3:27. "So to be down one goal, we knew we had a chance to steal a game. We came out in the third period and got some lucky bounces, and it found its way in."
Game 5 is Saturday night in Pittsburgh.
"Once again I'll go back to it -- we're not supposed to be here, no one picked us to," Canadiens left winger Mike Cammalleri said. "If we would say, 'Let's take two out of three going into Pittsburgh on Saturday,' I'd say, 'Why not?"
Silenced for nearly two full periods, the home crowd roared back to life after Lapierre swung around behind the net and whipped the puck off the back off Marc-Andre Fleury's right pad for the tying goal.
The fans had even more to cheer about moments later when Gionta's centering pass from the right side went in off Penguins defenseman Kris Letang's skate.
"It was pretty loud," Montreal defenseman Hal Gill said. "It was fun. That's a fun place to win and come back like that."
Fleury made 22 saves for the Penguins.
"They hung around," said Pittsburgh captain Sidney Crosby, held without a point for a third straight game. "I guess if you look at it, that's probably the difference."
Jordan Staal returned to the Penguins lineup six days after having foot tendon surgery. Staal, who missed Games 2 and 3, severed a tendon in his right foot on the skate of Canadiens defenseman P.K. Subban in Pittsburgh's 6-3 win in the series opener.
He had two shots on goal and played 13 minutes, 24 seconds.
"I didn't think he missed a step," Penguins coach Dan Bylsma said. "I think he looked pretty good."
Pyatt scored 2:34 in when his sharp-angle shot beat Fleury. It was a goal Fleury would surely like to play over.
Talbot tied it 53 seconds later with his scored his second of the playoffs at 3:27, beating Halak on a breakaway for an unassisted effort.
Kunitz put Pittsburgh ahead with a power-play goal at 5:18. The goal was reviewed because the puck went in off his left skate.
Montreal was outshot 15-6 in the first and 10-3 in the second. The Canadiens have been held to three shots in the second period five times in their last six playoff games.
Halak stuck out his right pad to stop Evgeni Malkin on a breakaway with about four minutes remaining. He also made a sensational lunging stop on Crosby during Pittsburgh's power play midway through the third.
Penguins right winger Bill Guerin missed his second game because of an undisclosed injury. Center Mike Rupp also didn't play. ... Pyatt scored two goals in 40 games during the regular season. ... Canadiens defenseman Jaroslav Spacek missed his eighth game because of a virus.