Mike Cammalleri scored two more goals, Halak made 38 saves in a performance much like his series-stealing play during Montreal's first-round upset of Washington and the Canadiens surprised the Penguins by winning 3-1 on Sunday.
Brian Gionta also scored as Montreal, playing without injured defenseman Andrei Markov, bounced back from a 6-3 loss in Game 1 and an early 1-0 deficit to even the Eastern Conference semifinal series at one game each.
Suddenly, a series the Stanley Cup champion Penguins are heavily favored to win doesn't look like a walkover after all.
"That's what we wanted to do, a series like this, we wanted to get one [in Pittsburgh]," Scott Gomez said. "It's far from over. But we came for one."
And they got it. Game 3 is Tuesday night in Montreal, followed by Game 4 on Thursday. The first playoff series between the teams since 1998 returns to Pittsburgh for Game 5 on Saturday.
"It's nothing to get frustrated about," Penguins forward Bill Guerin said. "We don't have to go and reinvent the wheel. They're a solid defensive team. They're well coached, they know what they're doing and you don't want to get down to teams like that."
Halak, pulled after allowing five goals on 20 shots in Game 1, made big save after big save as the Canadiens won despite being outshot 39-21. Crosby didn't score for the second consecutive game and neither did Evgeni Malkin, even though Pittsburgh's two stars skated together at times.
The Penguins were without center Jordan Staal because of a damaged tendon in his right foot -- the first game he's missed to injury in his four-season career -- but his absence didn't explain the Penguins' inability to solve Halak. Or Pittsburgh going 0-for-3 on the power play after being a perfect 4-for-4 in Game 1.
"They were a little bit more aggressive in the neutral zone and in their zone, but that's the playoffs, I mean everybody has got to adjust," Crosby said. "They're going to adjust and we're going to adjust. At the end of the day we've got to find a way to put the puck in the net."
Cammalleri did, putting Montreal ahead 2-1 by scoring on a power play in the second period. He sealed it by stealing the puck from Crosby at mid-ice and beating Marc-Andre Fleury on a breakaway with 2:54 remaining, his eighth goal in eight games.
"It all kind of came together," Gionta said. "The PK [penalty kill] stepped up, he [Halak] played well and we played without Marky [Markov] part of this year, and that kind of prepared us. We did it as a team, and that's what we've been doing the whole playoffs, playing as a team. It was a big effort."
And a dud for the Penguins, who didn't score after Matt Cooke swept a backhander past Halak 4:38 into the game.
Canadiens coach Jacques Martin didn't announce his Game 2 goaltender until minutes before game time after replacing Halak with Carey Price late in Game 1. After Cooke scored, Halak played much like he did while stopping 131 of the final 134 shots he faced against Washington -- when Montreal became the first eighth-seeded team to rally from a 3-1 series deficit and beat a top-seeded team.
The Canadiens had only one day to prepare for Pittsburgh after upsetting the Capitals.
"But we can't use it as an excuse [for losing Game 1]," Halak said. "We have to be ready for every game."
The Canadiens -- no longer contending with Staal, the Penguins' top penalty killer -- scored the final three goals.
Cammalleri, who has points in all but one of Montreal's nine playoff games, tied it by putting in a rebound of rookie defenseman P.K. Subban's deflected shot from the point at 7:29 of the second. The goal came 12 seconds into a power play created by Brooks Orpik's holding penalty.
Subban didn't get into the lineup until Game 6 against Washington, yet he played 23 minutes and 17 seconds while absorbing most of the 26 minutes a game Markov normally plays. Markov returned to Montreal for treatment for an apparent left knee injury after missing 37 games during the season with an injury much like Staal's.
Gionta had tied it at 15:48 of the first with his second goal in as many games. Gomez gathered a rebound of Benoit Pouliot's shot that deflected off the rear boards and steered it in front.
The Canadiens didn't draw a penalty until Hal Gill's interference penalty with 6 seconds left in the second period, then killed off three penalties over the next 10 minutes-plus. The lack of calls apparently contributed to Crosby's frustration.
"It's part of the game. He's their best player along with Malkin, and they were probably frustrated," Halak said. "But we aren't making the calls, the referees are making the calls."
Penguins forward Craig Adams drew a 5-minute penalty and was ejected for driving Marc-Andre Bergeron into the boards with 2:24 remaining. ... Extra policemen were deployed at Mellon Arena for security purposes after the Pittsburgh Marathon was disrupted briefly earlier in the day. Police discovered a suspicious device on a downtown street corner, but it apparently was not a bomb. ... Penguins D Jordan Leopold (concussion) played for the first time since being sidelined by an Andy Sutton hit April 16 against Ottawa.