PITTSBURGH -- The Montreal Canadiens probably didn't anticipate being quite this good so early in the season. The Pittsburgh Penguins certainly didn't expect to be this bad.

Tomas Fleischmann scored early in the third period after Montreal twice couldn't hold leads created by Max Pacioretty goals, and the Canadiens beat the winless Penguins 3-2 Tuesday night to sweep a season-opening four-game road trip.

Montreal hopes its early success under former Penguins coach Michel Therrien is an omen. The last time the Canadiens started 4-0, in 1977-78, they won the Stanley Cup.

With star centers Sidney Crosby and Evgeni Malkin again failing to score, the Penguins twice tied it after Montreal took the lead but lost for the 18th time in 23 games dating to last season, including the playoffs.

"We didn't want to give them (Crosby and Malkin) any confidence in that game," Pacioretty said. "I think we were hard on them early, I think we agitated them a bit. You could see they got a bit frustrated and that's the style we play."

The Penguins, outscored 8-3 so far while going 0-3-0, are off to their worst start since they were 0-4-4 in 2005-06, Crosby's rookie season. They lost their first four in 2001-02, prompting the firing of coach Ivan Hlinka.

Penguins coach Mike Johnston was happy "about 80 percent of the time" the way Crosby (4 shots) and Malkin (1 shot) played as his team outshot Montreal 33-30, but "it's been in and out. ... The third game of the season, and (already) you're clawing and scraping" for points.

It's a turnaround from a year ago, when the Penguins opened 10-3 in Johnston's first season as coach.

"Nobody likes to lose," Crosby said. "It's OK to be upset. ... You've got to find ways when you're 0-3."

Fleischmann, a left winger and longtime Penguins antagonist, won it by going to the net after center David Desharnais hauled down Pittsburgh left winger Sergei Plotnikov -- there was no penalty -- and took off with the puck. Fleischmann then beat goaltender Marc-Andre Fleury inside the near post with a wrister from along the left circle, his 12th goal in 27 games against Pittsburgh and first with Montreal.

"It feels like I score here a lot of times," Fleischmann said.

Fleury (27 saves) turned away excellent scoring chances by right wingers Devante Smith-Pelly and Dale Weise earlier in the period, both from only several feet away off turnovers, as the Canadiens pushed the pace with their trademark transition game.

"When they got loose pucks, they pushed it," Johnston said. "We gave them too much room. When they gain the (offensive) zone, they're a dangerous team."

Canadiens goalie Carey Price, 2-4-2 in his previous eight against Pittsburgh, made 31 saves in his third win of the season -- his best after a back door Crosby to Malkin pass set up an excellent scoring chance.

Pacioretty said, "That's the game right there, that one save."

Pacioretty scored twice for the second successive game, both times without a defender nearby, but Pittsburgh -- held to a single goal while losing the first two -- answered each time.

Pacioretty opened the scoring in the Penguins' home opener after right winger Brendan Gallagher skated hard into the left circle, whirled and threw the puck to his left winger, who one-timed it between Fleury's pads from above the circles at 5:46 of the first.

Gallagher isn't surprised the Canadiens -- who finally play at home Thursday night against the New York Rangers -- are playing so well on the road, where they were 24-13-3 last season.

"When the schedule came out, we were happy with the chance to start on the road, spend some time together and build as a team," he said. "Now we've got to go home and continue to play the same way."

Crosby finally took his first shot nearly 136 minutes into the Penguins' season, a wrister from the right circle that Price smothered. But third-line Penguins right winger Beau Bennett calmed what was becoming a restless Consol Energy Center crowd by scoring unassisted 5:31 into the second.

Bennett grabbed a loose puck in the Penguins' end, skated up ice into the right circle and snapped off a shot from the faceoff dot over Price's left shoulder.

Pacioretty scored his fourth of the season slightly less than three minutes later on a power play with a 35-foot wrister inside the near post as Gallagher screened in front. But Penguins defenseman Kris Letang tied it at 2 by knuckling a shot past Price, with winger Phil Kessel and Malkin assisting at 10:09 of the second.

It was Letang's first goal since March 19. He missed the final month of the 2014-15 regular season and the playoffs with a concussion.

"We're getting a little better ... but we need to get points, get on the board here," Fleury said. "It's disappointing, but it's early."

NOTES: The Penguins began a five-game homestand. ... Pittsburgh made one line change, moving LW David Perron to Malkin's No. 2 line and shifting LW Sergei Plotnikov to the third line centered by Nick Bonino. ... Pittsburgh scratched D Adam Clendening, D Tim Erixon and RW Bobby Farnham. ... Not surprisingly, Therrien didn't make any pre-game lineup adjustments. Not dressed were D Greg Pateryn, D Jarred Tinordi and LW Paul Byron. ... Price was back in goal after G Mike Condon made his NHL debut, making 20 saves while defeating the Ottawa Senators 3-1 on Sunday.