Alex Ovechkin is checked by Kris Letang during the Capitals’ 6-2 loss to the Penguins in Pittsburgh. (Gene J. Puskar/AP)

The Consol Energy Center crowd chanted his name, a mocking “Holt-by” serenading the Washington Capitals goaltender. A puck that Braden Holtby initially stopped with his shoulder had bounced up, rolled down his back and into the net.

That goal took a lucky bounce for the Pittsburgh Penguins, but the end result, a 6-2 loss for the Capitals, was indicative of exactly how lopsided a performance this was. A win would have clinched the top playoff seed in the Eastern Conference, but the loss instead showed that Washington still has work to do before the postseason, especially if a potential matchup with Pittsburgh awaits.

“They were in playoff mode,” Capitals Coach Barry Trotz said. “They wanted it more, and we got exactly what we deserved tonight.”

Washington trailed by just one goal after the first two periods, but then the Penguins scored three unanswered goals in the third, starting with Matt Cullen’s tally that rolled down Holtby’s back with 16 minutes 14 seconds to play. Less than four minutes later, Holtby was down on his stomach after a fifth goal got past him.

He stood up and looked at the videoboard to examine what went wrong this time. On the bench, backup Philipp Grubauer was fastening on his mask to replace Holtby.

The Capitals’ trouble went beyond just the goaltending. With three minutes left in the game, they had just 14 shots; the Penguins had more than twice as many, vastly out-possessing Washington.

That was partially because the Capitals racked up 41 penalty minutes, including 10-minute misconducts to Mike Weber (boarding) and Daniel Winnik (elbowing).

Though it didn’t happen Sunday, Washington still likely will clinch the top seed in the Eastern Conference, possibly this week. The Capitals still have a 19-point lead on the rest of the Metropolitan Division.

“We didn’t have our best night,” forward Jason Chimera said. “We’ve just got to move on from it and move to the next game. It’s one of those things where you’ve just got to forget about one of these games. They happen during the year, but you’ve just got to forget about it and move on. You’ve got to learn from it but move on.”

Said Trotz: “I’m not going to file it. I’m not going to let guys off the hook. There’s no excuse for the sloppy play, the lack of execution when heat was on. We had some guys I felt that were not strong tonight, and you can’t do that against a team that’s trending well.”

With the Capitals down 2-0 after 20 minutes, things became slightly unhinged in the second period. It started with a fluky goal by Chimera. The fastest player on the Capitals at 36 years old, Chimera raced to a loose puck in the Penguins’ zone, and goaltender Marc-Andre Fleury poke-checked his breakaway attempt.

But the puck bounced up and ricocheted off Chimera’s helmet, sailing over an unsuspecting Fleury and into the net, a goal better suited for soccer than hockey. The play stood after a lengthy review, and Washington had halved the deficit just 1:18 into the second period.

“Kind of a comedic goal, but you know, you’ll take them,” Chimera said.

The Capitals were penalized twice in the first period. In the second period, the shorthanded time continued to mount as the bitter rivalry showed itself.

A bruising exchange in Washington’s net between Bryan Rust and Weber led to Weber getting an extra roughing minor, putting the Capitals down a man.

On the ensuing Penguins power play, Pittsburgh appeared to score a goal after a flurry of shots directly in front of Holtby, but it was immediately waved off. Then a large scrum broke out behind the Capitals’ net, the result being roughing minors for Karl Alzner and T.J. Oshie and a roughing and slashing minor on Patric Hornqvist.

That put four Washington players in the penalty box: Oshie, Alzner, Weber and Andre Burakovsky, serving Weber’s extra roughing minor.

After Pittsburgh came up empty on its power play, Burakovsky broke out of the box, pounced on a loose puck for a breakaway and beat Fleury to tie the game 15:12 into the second period.

The Penguins quickly recovered their lead when Tom Kuhnhackl scored on the shift after Burakovsky’s goal, giving Pittsburgh a 3-2 lead at the second intermission.

That goal started with defenseman Nate Schmidt losing a battle at the wall to Kuhnhackl and turning the puck over and then “one of our D was lazy coming back,” Trotz said, referring to Dmitry Orlov.

“If you want to go far here in the playoffs, we can’t play like this at all,” Burakovsky said. “I think Pittsburgh is coming out and being playoff-ready, like they’re ready to go. If you’re looking at our game today, we’re doing way too many mistakes. If you look at Pittsburgh, they’re managing the puck, and you don’t find a whole lot that they’re doing wrong.

“That’s something we have to think about.”