Jarome Iginla and James Neal each scored twice, Crosby, Chris Kunitz and Pascal Dupuis added goals, and Tomas Vokoun made 30 saves. Down 2-1 after the first period, the Penguins scored twice in a 40-second span early in the second and added four goals in the first 10 minutes in the third.
Milan Michalek, Kyle Turris and Daniel Alfredsson scored for Ottawa. Senators goalie Craig Anderson was benched after Pittsburgh's sixth goal, and Robin Lehner finished the game.
"There was a sense like, 'OK, this might take as many shots as we can muster to break this guy.' And fortunately, we kept on that mindset," Penguins coach Dan Bylsma said. "It was a matter of, 'We are going to have to fire anything and everything we can at this guy to get one by him.'"
"I know what we're going to do," Alfredsson said. "We're going to go out and play one hell of a game. That doesn't worry me at all. We never quit and that's not going to stop now. We know the odds are against us in every way, but we never quit and that's going to continue."
The Senators opened the scoring on Michalek's short-handed goal at 2:29 of the first period. It was the Senators' first lead of the series. It wouldn't last.
Neal tied it with 5:04 left in the period. Turris put Ottawa back in front off a rebound with 3:45 left in the first.
Pittsburgh tied it early in the second when Kunitz got behind the defense and went in alone to beat Anderson. Less than a minute later, Anderson gave up a rebound on Kris Letang's shot that landed on the tape of Iginla's stick to make it 3-2.
Neal started the third-period flurry with a power-play goal at 1:59. Dupuis added a short-handed goal at 8:07, Crosby followed at 8:39, and Iginla scored on a power play at 9:53.
Pittsburgh 7, Ottawa 3
Penguins lead series 3-1
• Boston at N.Y. Rangers, 5 p.m.
Bruins lead series 3-0
• Chicago at Detroit, 6 p.m., NBCSN
Red Wings lead series 2-1
• San Jose at Los Angeles, 8:30 p.m., NBCSN
Series tied 2-2