"Today, we did it pretty well in the first period, and then it got away from us a little."
The Red Wings played their final game on home ice this season, finishing 18-16-7.
"I thought we were pretty good at home in the first half of the season, and I thought the fans helped us a lot with their energy," Detroit defenseman Danny DeKeyser said. "In the second half of the season, I thought we got a little stagnant at home, and I don't know why."
Chad Ruhwedel gave the Penguins a 1-0 lead at 13:44 of the first period, knocking in Teddy Blueger's pass for his fourth goal of the season.
Less than two minutes later, the Red Wings left Crosby alone and he tapped in Rickard Rakell's pass for a 2-0 lead at 15:18.
Jakub Vrana cut it to 2-1 with a power-play goal at 16:36, and Michael Rasmussen tied it 2-2 by finishing a 2-on-1 break 17 seconds into the second.
The Penguins responded with five unanswered goals, starting when Rakell made it 3-2 at 7:44.
Letang then pushed the lead to 4-2 at 11:37.
"That was a huge goal by [Rakell]," Sullivan said. "I thought we kept playing well after they tied it, but getting that goal really settled things down for us."