Capitals goaltender Philipp Grubauer denies Penguins captain Sidney Crosby during Washington’s 3-1 win Sunday in Pittsburgh. (Gene J. Puskar/Associated Press)

There was Sidney Crosby, dropping down on one knee to smack in the rebound. But there, too, was Philipp Grubauer, legs split across the crease as he leaned to the left with his glove outstretched. Grubauer caught the puck, and even the Pittsburgh Penguins’ home crowd couldn’t help but cheer the visiting goaltender’s effort. Grubauer had flopped onto his stomach but then stood and regained his place in net.

The Washington Capitals claimed their third straight Metropolitan Division title with their 3-1 win over the second-place Penguins at PPG Paints Arena on Sunday night. It’s a validating accomplishment for a Washington team that faced lower expectations after summer salary-cap constraints forced significant roster turnover and an increased reliance on less experienced and cheaper players this year.

“I think it’s important,” Capitals forward T.J. Oshie said. “It’s kind of a goal that you set at the beginning of the season that we can kind of just check it off. I don’t think we want to look too much more into it. We don’t want to pat ourselves on the back too much. . . . I think a lot of guys worked very hard for it. But we still have a lot we want to do here.”

To have that lengthy, successful playoff run that has for so long eluded these Capitals, they will need good goaltending. But Coach Barry Trotz will first have to make a choice between two-time Vezina Trophy finalist (and 2015-16 winner) Braden Holtby, Washington’s rock for the past six seasons, and Grubauer, who started the season as the No. 2 netminder and has played his way into consideration to start the postseason. On Sunday night, Grubauer may have made himself the front-runner with his 36-save performance.

“He played well in this building,” Trotz said. “We’ve wanted both of our goalies to both make a statement. Holts has done that all year, and he’s going to get a chance to do it [Monday in St. Louis]. We want both our goalies going really well, and they are. So that’s good on us.”

Trotz has dismissed that the team has a “goaltending controversy,” but for the first time in Trotz’s four seasons in Washington, it’s unclear whether Holtby will be the playoff starter. Trotz rotated Grubauer and Holtby from one game to the next, but it’s significant that he chose to start Grubauer in arguably Washington’s most important regular season game.

“It’s nice to get the call not on the back end of a back-to-back,” Grubauer said. “But other than that, it’s just a game.”

While Holtby struggled during the second half of the season, Grubauer has been quietly making a case for more responsibility since late November — he entered Sunday’s game with an impressive 1.88 goals against average and a .938 save percentage in his past 25 appearances — but this marked his first career start against the Penguins. Trotz said it was an “opportunity” for Grubauer. Perhaps it was also a test to see how he would handle an opponent the Capitals have lost to in the second round of the playoffs the past two seasons and could see again this postseason.

“He was unstoppable,” said captain Alex Ovechkin, who played his 1,000th career game Sunday. “He was unbelievable. I think he reads the play well. He makes unbelievable saves, keep us in the game.”

Through the first two periods, Grubauer was the Capitals’ best player. Oshie lifted Washington to a 1-0 lead 6:25 into the game. But fourth-line center Jay Beagle left the bench and went to the locker room with 4:39 left in the first period, and he was ruled out for the rest of the game with an upper-body injury. Beagle is one of Washington’s top penalty-killing forwards, and without him to help kill them off, the Capitals were called for five minor penalties in the second period alone.

Pittsburgh entered with the NHL’s best home power play (28.1 percent), and Washington had allowed six power-play goals on 14 opportunities in the teams’ first three meetings. But Grubauer and the Capitals were flawless in four man-advantages for the Penguins in the second period. After Washington was called for too many men on the ice, defenseman Matt Niskanen sailed a puck over the glass just 40 seconds into the Penguins’ power play, awarding Pittsburgh 1:20 of five-on-three time. Grubauer caught a break when star sharpshooter Evgeni Malkin had a shot go off the crossbar, but Grubauer made seven saves between the two penalties.

“What all of us already saw he could do, we’re just seeing it in games,” Oshie said. “He works as hard as anyone in practice. . . . I’m not surprised by his play. I’ve said it all along: We’ve got two No. 1 goalies, and everyone else is starting to realize that now.”

Tom Wilson, another one of Washington’s top penalty killers, was called for tripping 11:38 into the period, and Grubauer made three more shorthanded saves. Then, just as Wilson’s penalty expired, defenseman Dmitry Orlov led the rush up the ice before firing from the high slot and getting a wrist shot past Matt Murray to lift the Capitals to a 2-0 lead through 40 minutes despite some self-inflicted trouble. Grubauer saved 26 shots in that span, with 12 of them with the Penguins on the power play. He even shoved notorious net-front nuisance Patric Hornqvist out of his crease several times.

Then, 23 seconds after the Capitals came out of the tunnel for the third period, Wilson redirected a Niskanen pass from the point to give Washington a cushy 3-0 lead. On the other end of the ice, Grubauer went through his motions, backing into his net and touching both posts before getting back into position.

He could be spending a lot of time there in the coming weeks.

“It’s huge,” Ovechkin said. “The hot goalie is a hot goalie. They can win the game for us. I hope they’re going to play like that in the playoffs, and we’re going to have a chance.”