David Steckel scored the other goal for the Capitals, who hadn't won the first two games of a playoff series since the 2003 Eastern quarterfinals against Tampa Bay.
Sidney Crosby had a three-goal game for the Penguins, who were also down 0-2 in their 2008 Stanley Cup Finals with eventual champion Detroit. Pittsburgh goalie Marc-Andre Fleury allowed four goals on 33 shots.
The series moves to Pittsburgh for Game 3 Wednesday.
2014: NFL Cheerleaders [PHOTOS]
Michael Sam cut from the Dallas Cowboys