Shayne Gostisbehere and Claude Giroux scored in the third period for Philadelphia (13-9-3). Carter Hart made 11 saves after relieving Brian Elliott, who was pulled 3:05 into the second period after allowing three goals on 10 shots.
"I thought we played a good game from start to finish," Flyers coach Alain Vigneault said. "Guys competed. We're not going to be perfect, but we competed hard, made some good plays at the right time, got some good looks. Unfortunately the game results-wise didn't go our way, but our battle level was there and we worked right until the end."
Ovechkin made it 4-2 at 13:10 with his 263rd power-play goal, which is two behind Brett Hull for second in NHL history. Dave Andreychuk is first with 274.
Nic Dowd made it 5-2 at 4:25 of the third period. Washington's fourth line of Dowd, Hagelin and Garnett Hathaway (two assists) combined for five points Saturday, and eight points (four goals, four assists) in the three games against the Flyers.
"There is a good balance right now," Capitals coach Peter Laviolette said. "There are no different rules for different lines, and no different roles. Everybody has the same rules with regards to how we play defense, how we attack offensively, and from there you have to work to create or work to defend. So the fact that we are getting contributions both defensively and offensively from all four lines I think is a real positive thing."