The Capitals outshot the Penguins 13-9 in the second period, and even scored the first goal of the game, but find themselves trailing by one heading in to the third period.
Mike Knuble scored 1:09 in to the period, his 26th of the year, on a rebound of a Nicklas Backstrom shot to give the Capitals a 1-0 lead.
Backstrom was stopped in the slot by Fleury, but the puck deflected straight up and landed behind Fleury. Knuble poked in the loose puck before it rolled passed the net.
Pittsburgh responded just 1:13 later on a deflection. Maxim Talbot, last year's hero for the Penguins in Game 7 of the Stanley Cup Finals, deflected Brooks Orpiks shot from the top of the right circle passed Theodore at 2:21.
Theodore attempted to push a rebound to Joe Corvo, but Corvo over skated the puck, which allowed Craig Adams to scoop it up and pass to Orpik.
After a tripping call on Tomas Fleischmann at 13:44, Bill Guerin put Pittsburgh in front for the first time on a one-timer from the low slot on a pass from Crosby. The Capitals failed to clear the puck, and as Crosby charged the net he found a wide open Guerin who easily put home the one-timer.