Ovechkin gave the Capitals a 2-0 lead when he got the rebound of Jakob Chychrun’s shot and chipped a backhanded shot past a lunging Jordan Binnington from below the right circle at 2:39 of the second period.
It was the third goal of the season for Ovechkin, who broke Wayne Gretzky’s all-time goals record when he scored his 895th career goal on April 6 in a 4-1 loss at the New York Islanders. Ovechkin reached the 900-goal mark in his 1,504th career game.
Anthony Beauvillier and Tom Wilson each had two goals, and John Carlson had a goal and an assist for the Capitals (7-5-1), who had lost four straight (0-3-1). Chychrun had three assists and Logan Thompson made 23 saves.
Alexey Toropchenko scored for the Blues (4-8-2), who have lost eight of nine. Binnington allowed four goals on 15 shots before being lifted at 9:28 of the second period. Joel Hofer made 16 saves in relief.
Wilson gave the Capitals a 1-0 lead at 9:50 of the first period, scoring from the slot when he deflected Carlson’s slap shot from the point during a power play.
Beauvillier made it 3-0 at 4:33 of the second period when he faked a wrist shot from the slot and scored on a backhanded shot from just outside the right circle.
Carlson increased the lead to 4-0 at 9:28, spinning around in the slot and scoring on a snap shot.
Beauvillier scored his second of the night when he got to a loose puck on the rush and beat Hofer from the left circle to make it 5-0 at 16:20.
Toropchenko pulled the Blues within 5-1 when he lifted a backhanded shot over Thompson for a short-handed goal 37 seconds into the third period.
Wilson knocked in a Rasmus Sandin rebound for his second of the night for the 6-1 final at 9:00.