BOSTON — The Washington Capitals were so dominant this season that they had nothing left to play for with two games remaining in the regular season.

That’s precisely why the Bruins want to avoid them in the playoffs.

“In retrospect, it’s over and we’re through it,” Boston forward David Backes said after the Bruins finished the regular season with back-to-back losses, falling 3-1 to the Capitals on Saturday to set up a potential first-round matchup with Washington. “We did what we could through 82 games, and we can’t change it now.”

Kevin Shattenkirk scored the go-ahead goal 56 seconds after the Bruins tied it in the second period, and backup goalie Philipp Grubauer made 21 saves for the Capitals. Marcus Johansson and Justin Williams also scored for Washington, which has won 10 of its last 11 games.

The Bruins will start the playoffs on the road, but they still have a chance to avoid Washington in the first round if Toronto loses in regulation Sunday against Columbus. The Maple Leafs need one point to pass Boston and finish third in the Atlantic, which would make the Bruins a wild-card team and send them to Washington. Otherwise the Bruins would face Ottawa in the first round.

“Now we’re scoreboard-watchers,” Backes said. “That’s all we can do.”

Bruins No. 2 goalie Anton Khudobin stopped 21 shots in the first two periods before he was replaced by starter Tuukka Rask. The team said Khudobin wasn’t feeling well. Rask stopped all eight shots he faced in the third period.

Jakob Forsbacka Karlsson, a Swedish forward who signed with the Bruins after completing his sophomore season at Boston University, became the 10th player to make his NHL debut for the Bruins this season. Defenseman Torey Krug, who left Thursday night’s game against Ottawa because of a leg injury, did not play and the Bruins also lost rookie defenseman Brandon Carlo late in the first period after he was checked head-first into the boards by Alex Ovechkin.

MAPLE LEAFS 5, PENGUINS 3: Connor Brown broke a tie with 2:48 left and Toronto won at home to wrap up its first playoff spot since 2013.

James van Riemsdyk, Tyler Bozak, Kasperi Kapanen and Auston Matthews also scored for Toronto, and Curtis McElhinney stepped in for an injured goalie Frederik Andersen with 12 saves in the third period.

Toronto’s win eliminated both Tampa Bay and the New York Islanders from contention for the last remaining playoff berth in the Eastern Conference.

Phil Kessel, Sidney Crosby and Jake Guentzel scored for Pittsburgh.

SENATORS 3, RANGERS 1: Ottawa wrapped up second place in the Atlantic Division and home-ice advantage in the first round of the playoffs with a win over visiting New York.

Mike Hoffman, Derick Brassard and Jean-Gabriel Pageau scored, and Craig Anderson made 18 saves for the Senators.

Mike Zibanejad scored for New York, and Henrik Lundqvist stopped 30 shots.