Washington winger Tom Wilson, left, is tripped by Pittsburgh center Sidney Crosby. The transgression sent Crosby to the penalty box in the first period of Wednesday night’s game at Verizon Center. (John McDonnell/The Washington Post)

The Washington Capitals began Wednesday night poised for a season sweep of the Pittsburgh Penguins. They already had won their first three meetings against their Metropolitan Division rivals — each filled with violence and vitriol — but they spent the fourth meeting at Verizon Center trying to dig out of their own holes.

By the time the horn blew on their 4-3 loss, they had squandered a chance to leap the Penguins in the standings.

“Our focus wasn’t where it should be, where I expect it to be, and where it needs to be to play a very good team,” Coach Barry Trotz said. “We had good focus the first three times and we got victories. Tonight we weren’t as focused, and we deserved a loss.”

Trotz’s seven-minute postgame dissection was largely spent listing his displeasures from the loss. They included a slow start that saw the Capitals go eight minutes without a shot on goal, seven minors committed during the second period and six Pittsburgh power plays.

The penalties committed were “unacceptable.” The opening period, carried over from a similarly slipshod morning skate, was “sluggish.” They allowed a shorthanded score for only the second time this season, fell in regulation for the second straight game and, by the second intermission, had mustered fewer power-play shots on goal than attempts while trying to kill penalties.

Post Sports Live debates Alex Ovechkin's chances of winning the Hart Memorial Trophy again and whether the Capitals left wing is even the most valuable member of his team. (Post Sports Live/The Washington Post)

Sure, Trotz noted, the Capitals clawed back three times from two-goal deficits, and here he sought brief solace. The last came with less than five minutes left, after Penguins goaltender Marc-Andre Fleury bashed forward Joel Ward in the knee and took a roughing penalty. But forward Alex Ovechkin’s league-leading 39th goal, scored with less than four minutes left, instead served as Washington’s final gasp, one last belch of fuel in another head-scratcher.

“We showed a little fight in the third, a little push,” defenseman Matt Niskanen said. “Not enough today, though. We weren’t good enough today.”

The Capitals had expected an ornery visitor bent on avoiding the wrong side of history — a Washington win would have marked the first time Pittsburgh failed to gain at least one standings point against the Capitals in a single season — and predicted Wednesday would bring a cleaner, more focused hockey game than its previously scrap-heavy meetings.

Those dreams lasted until the eight-minute mark, when all hell broke loose. After Penguins forward Patric Hornqvist scored the game’s first goal, Capitals forward Michael Latta rushed to the aid of teammate and roommate Tom Wilson, who had been hauled onto the Penguins’ bench. The Gatorade cooler tumbled over. A brawl staged outside the bounds of play. Only four roughing minors were handed out, the appetizer to a night chock full of the stuff.

It was never worse than when Niskanen tried to dump the puck behind to forward Andre Burakovsky and, instead, it skittered into open ice. While Pittsburgh captain Sidney Crosby sat for holding Wilson, forward Brandon Sutter gathered the wayward puck and deked past goaltender Braden Holtby, putting the Penguins up 2-0, just the second shorthanded goal allowed by Washington this season.

Only after defenseman John Carlson crushed his 10th goal past Fleury on the opposite end, rifling forward Jason Chimera’s drop-back pass, with 8.6 seconds left on the clock, could the Capitals retreat in the locker room with some trace of life.

But like Pittsburgh did in the opening period, committing two minors within five minutes, Washington began the second on an undisciplined bender, booking three quick tickets toward the box. The Capitals successfully killed Ward’s slash and defenseman Cameron Schilling’s interference, but the middle penalty — forward Brooks Laich’s trip, 10 seconds after Ward released — buried them into another two-goal hole.

Capitals goaltender Braden Holtby stops Sidney Crosby in the third period with an assits from Matt Niskanen. (John McDonnell/The Washington Post)

“Taking 14 minutes in penalties in the second period, there’s no way you’re going to be able to win a hockey game,” forward Troy Brouwer said.

Through thick traffic, mostly generated by red sweaters, Crosby whipped the puck into the net while Holtby tried to peek around for a sightline. As the Penguins celebrated, Holtby tossed his head back, dejected upon already allowing two more goals in less than 24 minutes Wednesday than he had in the previous 180 against Pittsburgh this season.

The Capitals eventually survived Chimera’s offensive holding, Wilson’s cross-checking and Schilling’s hooking, which gave Pittsburgh its fourth, fifth and sixth power plays, all during the same period. They still searched for an offensive pulse, but were fortunate to be fighting only so far uphill.

When Chimera threaded a nifty pass ahead to forward Troy Brouwer, who swatted his own rebound 4 minutes 9 seconds into the final period, the Capitals had once again pulled within one goal. Then, three minutes later, Malkin picked away the puck from forward Kuznetsov in the neutral zone and, in the crease, forward Chris Kunitz boxed him out for the rebound goal. Kuznetsov hacked his stick onto the crossbar. The knockout punch had appeared to come. It wound up simply serving as the winning goal.