Backstrom now has 18 points in his last 13 games (four goals, 14 assists). Washington improved to 12-2-0 in its last 14 games.

Goalie Braden Holtby, who is in a battle with Philipp Grubauer for the starting job, made 34 saves for Washington in the win and was solid in net.

St. Louis was one point behind Colorado for the second wild card in the Western Conference and two behind the Kings for the top wild card coming in and couldn't gain ground.

Those two teams play each other late Monday night.

In this game, the Blues took a 1-0 lead on the only goal of the first period, a Vladimir Tarasenko shot from between the circles at 3:38.

Washington then answered with three goals in just over seven minutes in the first part of the second period.

Backstrom tied the game with his 20th goal of the season by spinning and putting a high shot past goalie Jake Allen 51 seconds into the period. Jakub Jerabek then made a long pass that sprung Alex Chiasson on a breakaway for his goal at 2:39.

Andre Burakovsky wrapped up the three-goal run with some dazzling moves that got him past a few St. Louis defenders, and he also sent a high shot by Allen at 7:54 which gave the Caps a 3-1 lead.

Patrik Berglund made it 3-2 with 8:22 remaining in the second period when his shot from the right banged off Matt Niskanen of Washington and past Holtby from near the crease.

Alex Ovechkin added a late empty-net power-play goal for the 4-2 final.

The Capitals clinched their third straight Metropolitan Division title with a win on Sunday in Pittsburgh, and this was their final road game. They end the season with home games versus Nashville (Thursday) and New Jersey (Saturday).

The Blues host Chicago on Wednesday and end their season with road games at the Blackhawks (Friday) and Colorado (Saturday).

If St. Louis does make the playoffs, it will be without Scottie Upshall, who suffered a lacerated kidney on Saturday, the team announced Monday.

--Field Level Media