Washington coach Barry Trotz won in his first game with the team. He mixed veterans - including Holtby and Alex Ovechkin - with prospects, while Buffalo's Ted Nolan used a relatively inexperienced lineup.
Copley stopped six shots in the first period, and Holtby made 19 saves over the final 40 minutes. Nathan Lieuwen made 24 saves for the Sabres.
Burakovsky scored with 6:46 left in the third. The 2013 first-round pick took a pass from Jason Chimera in the right circle and beat Lieuwen.