Ovechkin took three shots and delivered several checks. With 3:03 left in the game, Ovechkin got into a shoving match after being run into the boards headfirst by Gregory Campbell. Ovechkin retaliated by slashing Campbell with a one-handed stick swing, and both players earned minor penalties.
The Capitals are unbeaten in three exhibition games.
Alexander Semin's power-play goal late in the second period snapped a 1-1 tie. Mathieu Perreault and Cody Eakin also scored for Washington.
Jeremy Reich and Brad Marchand had goals for the Bruins.