Washington's Jakub Klepis scored on a power play with 1:16 to play in regulation to force the overtime in the matchup between the teams with the two worst records in the Eastern Conference last season.
Sergei Gonchar had two power-play goals and Ryan Whitney added two assists for the Penguins, who have lost two of three games this week.
Klepis added two assists for the Capitals (1-0-1).
Pittsburgh rookie Evgeni Malkin did not play after dislocating his left shoulder in his NHL debut two nights earlier.
The player taken one spot above Malkin in the 2004 NHL Draft -- fellow Russian Alexander Ovechkin -- did not play for Washington because of precautionary reasons after sustaining a knee-to-knee hit in a game Wednesday night against Tampa Bay.
Sidney Crosby, the 2005 No. 1 overall pick, did not dress for the Penguins because he played Tuesday and Wednesday and plans to play Saturday in a game in Hamilton, Ontario.
Pittsburgh veteran winger Mark Recchi also did not play after he broke a cheekbone Wednesday night in New Brunswick.