The victory gave the Penguins a commanding 3-1 lead in the best-of-seven series. Game Five is in Washington on Saturday.
Crosby, who led the NHL with 44 goals in the regular season, missed the game after suffering a concussion early in Game Three.
Pittsburgh built a 2-0 lead on goals by Patric Hornqvist and Jake Guentzel, blew that by giving up quick-strike goals to Evgeny Kuznetsov and Nate Schmidt and took a 3-2 lead into the third period after Justin Schultz scored on a power-play.
The Capitals dominated the third but could not beat Pittsburgh goaltender Marc-Andre Fleury, who made 36 saves and became the 15th goaltender in the NHL to reach 60 playoff wins. Washington goalie Braden Holtby stopped 15 shots.
Ducks 4, Oilers 3 (OT)
Ryan Getzlaf had two goals and two assists, including a helper on Jakob Silfverberg’s goal at 45 seconds of overtime, as Anaheim rallied from two goals down to defeat Edmonton and even up their best-of-seven series at 2-2.
Getzlaf stole the puck in the Oilers’ zone and made a cross-ice pass that Silfverberg ripped into the net past goaltender Cam Talbot. The road team has won all four games in the western Conference semi-final series.
With his second goal of the contest – Getzlaf’s 36th career playoff marker – he surpassed Teemu Selanne as the Ducks’ all-time leading post-season goal scorer.
Anaheim unleashed 21 shots in the second period, when it scored twice to tie the game at 2-2.