Crosby scored one goal and had another disallowed.

"Instead of going out there and trying to set the tone ourselves, I think we tried go out there and feel things out," Crosby said. "When you do that, you get caught watching sometimes and unfortunately they were able to get a lead on us."

The 19-year-old Crosby, who led the NHL with 120 points, scored the game's final goal at 19:11 for his first playoff point. He also had a goal waved off 37 seconds into the third after Dany Heatley put Ottawa up 4-1 with a power-play goal 28 seconds earlier.

"That actually helped us bear down and focus a little more," Preissing said. "When we did restore that three-goal lead, maybe we let up a little bit, and I think that non-goal helped restore our focus."

Chris Neil and Mike Comrie added third-period goals, and Ray Emery stopped 23 shots for Ottawa, which went 31-7-8 from Dec. 23 to the end of the season.

"For sure that was not the start that we were expecting," Penguins coach Michel Therrien said. "You've got to give credit to Ottawa. They played a really solid game. They beat us in every aspect of tonight's game."

Jordan Staal and Sergei Gonchar scored for Pittsburgh, which played its first playoff game since 2001.

Fleury made 30 saves before he was replaced by Jocelyn Thibault during a stoppage in play midway through the third with Ottawa leading 6-1.

"Right away they got a goal and it just seemed like they were always there, always coming back for more," Fleury said.

Game 2 of the best-of-seven series is Saturday in Ottawa.

"We know they're a dangerous team, whether they're young or not," Heatley said. "We'll just worry about ourselves and the way we play."

Along with Crosby, Staal and Fleury, Evgeni Malkin was one of 13 Penguins who played their first career playoff game.

"The positive thing is that the first game is under their belts," Therrien said. "I didn't think our team was tight, but I guess they were. We can't do worse than that. That's probably one of the worst performances we had this year."

Penguins owner Mario Lemieux was looking on from a luxury box as Ottawa jumped on his young team.

Meszaros opened the scoring 1:37 in when he put a shot from the high slot into an open net as Fleury lay sprawled on the ice.

Kelly made it 2-0 at 6:38, beating Fleury after taking the puck from defenseman Mark Eaton, who was on his knees after blocking Joe Corvo's shot.

"It was frustrating," Eaton said. "I blocked it, I thought it was under me and I didn't really know where it was until I saw it on his stick. By then it was too late and I wasn't able to get it back from him and he finished."

Corvo got his second assist on Preissing's power-play goal in the second before Staal gave Pittsburgh some hope with 3:02 remaining in the third. He slipped a puck inside the right post to make it 3-1 after Emery was unable to cover up a loose puck.

Crosby, booed sporadically by the sellout crowd of 19,611, drew cheers when he was penalized for hooking late in the second.

Heatley, the first player to reach 50 goals in consecutive seasons since Florida's Pavel Bure in 2000 and 2001, scored early in the third with 2 seconds remaining in Crosby's penalty.

Crosby appeared to have drawn Pittsburgh back within two when the puck got past Emery after he drove the net as Colby Armstrong shot the puck from the right side.

The crowd erupted in cheers when a video review determined that Crosby kicked the puck in as he slid toward the goal.

"I thought for sure it was going to be a goal," Crosby said.

Neil made it 5-1 when he beat Fleury on a backhand at 5:39. Comrie increased the lead to 6-1 at 8:22.

Thibault replaced Fleury at 10:28 and Gonchar scored on a 5-on-3 power play at 12:42.

Notes:@ Lemieux had one point, an assist, in his first career playoff game, a 3-1 win over the New York Rangers on April 5, 1989. Wayne Gretzky had a goal and an assist in his playoff debut on April 8, 1980, a 4-3 overtime loss by Edmonton in Philadelphia.