RW Bryan Rust returned to the lineup Tuesday after missing his team's first three games with injury.
RW Phil Kessel scored on the power play and teamed with Matt Cullen to give Pittsburgh a two-goal lead with a pair of quick goals midway through the first period.
F Matt Cullen, filling in for Sidney Crosby (concussion) as the Pens' top-line center, made it 2-0 by scoring off his own rebound in front at 9:33.
G Marc-Andre Fleury made 27 saves but couldn't make a 28th in overtime. "He swung at it, and it just rolled up over me," Fleury said. "It's disappointing. I don't like losing on a shot like that."