Alex Ovechkin and the Capitals suffer a second straight loss for just the third time this season. (Marcio Jose Sanchez/AP)

SAN JOSE – Everything was proceeding according to schedule for the Washington Capitals. They were trailing after the first period and then tied after the second, leaving the third period to pull away from the San Jose Sharks, as they have from most teams this season.

But the Capitals’ typical routine failed them, and for just the third time this season, suffered consecutive losses, falling in San Jose, 5-2, after allowing two goals in the first four minutes of the third period. Entering the game, Washington had the best third-period goal differential in the league, plus-36 in the final frame.

Washington ends its four-game road trip that started in Boston and weaved through California with five out of a possible eight points, with all four games coming against playoff-bound teams.

A win would have officially clinched a postseason appearance for the Capitals, essentially a formality for a team with 103 points with 14 games left in the season. But the loss extended what’s been at times a concerning string of games for Washington, which hasn’t held a lead in any game since March 2 against the Toronto Maple Leafs, and is 2-2-1 in five games since. The wins were in overtime or a shootout.

“We’d like to play with the lead,” Coach Barry Trotz said. “I think we’re a better team with a lead. We haven’t had it for a while, so we’ve been chasing the game the whole time. To be 2-2-1 against the quality of opponents that we’ve played in the last five games, that’s not bad.”

A 2-2 game after 40 minutes, the Sharks started the third period on a power play after Evgeny Kuznetsov was called for hooking with 41 seconds left in the second. It took the Sharks less than a minute to score after intermission, as goaltender Philipp Grubauer left a window between his body and the post, and Joe Pavelski beat his short side.

“It was a gift,” Grubauer said. “A gift from me.”

What stung was the San Jose goal just two minutes later, a shot from Brenden Dillon at the point that got through because Grubauer was screened by Dainius Zubrus and Brooks Orpik. With no power-play opportunities in the third period, the Capitals couldn’t recover from the two quick goals. Brent Burns added an empty-netter in the final minute.

“They had all of the energy, they had all of the jump,” Trotz said. “They were first to pucks, and we got away from what we needed to do.”

A rash of slow starts have been a popular conversation topic in the Capitals’ locker room. On Wednesday, they fell into a 3-0 hole in the first period before storming back with three goals in the third period to force overtime and pull a point against the Kings. They were proud of their resiliency, boasting a refusal to quit despite resting comfortably atop the standings, but they were also frustrated with constantly being in a position to have to rally.

The trend continued Saturday, when Washington again found itself trailing early when Grubauer couldn’t collect a rebound off a Dillon point shot with Joe Thornton screening him. Thornton punched in the loose puck 9 minutes and 16 seconds into the first period. It marked the 13th game in the Capitals’ last 15 that the opposing team scored first.

Washington got goals from T.J. Oshie and Justin Williams in the second period, both tallies tying the game. A lead has still eluded the Capitals.

“It’s really tough coming from behind every night,” Williams said. “It seems like we’re obviously used to it. It’s been happening quite a bit. I mean, we just need to stop thinking about it and just go out and play. Our starts obviously have been issues for us, our first-period goal differential, all that. It’s something we have time to clean up.”