T.J. Oshie and the Capitals couldn’t hold off old friend Nate Schmidt and the Golden Knights. (Katherine Frey/The Washington Post)

Alex Tuch took a back-and-forth contest and, by willing the puck through Philipp Grubauer, made sure the final tally was in the Vegas Golden Knights’ favor.

Grubauer, the Washington Capitals’ backup goaltender who started the game, went to glove Tuch’s point-blank shot as it trickled toward the goal line and instead knocked it into the net. That came with 5:12 left in the third period and held as the game-winner in the Knights’ 4-3 victory at Capital One Arena on Sunday.

The Golden Knights (35-13-4) started the season as the NHL’s 31st team and have, improbably, become one of its best, sitting atop the Pacific Division with the second-best record in the league. The Capitals (30-17-5) led in the first, second and third periods, and missed a chance to extend their three-point lead over the second-place New Jersey Devils in the Metropolitan Division. The Capitals recorded just 23 shots on goal, while the Golden Knights finished with 31. Washington has given up a combined 11 goals in back-to-back losses.

“We’re just giving up too good of chances right now,” Capitals defenseman Matt Niskanen said. “Ideally, you wouldn’t give up too many chances at all because you’re attacking and you have the puck more, but at the very least you have to deflect the puck to the outside and keep things on the perimeter. Other teams are getting too many free looks.”

Philipp Grubauer gets beat by Reilly Smith in the second period. (Katherine Frey/The Washington Post)

It was the first time the Golden Knights visited Washington, as the Capitals were shut out in a loss at Vegas in December. The Knights’ season of firsts — first game, first win, first expansion franchise to reach 34 victories in an inaugural season — has also been a season of reunions for the players plucked off rosters in June’s expansion draft. That has given life to otherwise innocuous midseason games, like a Thursday night contest in St. Louis, Tuesday in Calgary or, with the return of defenseman Nate Schmidt, a matinee against the Capitals on Super Bowl Sunday.

Schmidt played in Washington for parts of four seasons and became a fan favorite with his swift skating and easy grin. He now serves as a reminder of the blue-line depth the Capitals lost over the summer, as Schmidt went from an established team with Stanley Cup hopes to a franchise hoping to just establish itself.

The Golden Knights have done that, and then some.

“Guys were exposed [in the expansion draft] for many different reasons, so they said, ‘Maybe we go to this new place in Vegas to get our games back,’ ” Schmidt said Sunday morning. “I think, at the end of the day, the no-expectations thing, it makes it easier for our guys to play. There’s no pressure. And when you can play with no pressure, and go out and play with confidence and the team’s playing well, that’s the best of both worlds.”

The goaltender in front of Vegas’s net also provided a reminder of sorts, though one not as welcomed as Schmidt’s return. It was the first time Marc-Andre Fleury played in Washington since he, while playing for the Pittsburgh Penguins, blanked the Capitals in Game 7 of the Eastern Conference semifinals in May. Fleury came into the game with an 11-3-1 record in his past 15 starts but gave up a goal to Capitals winger Chandler Stephenson on the third shot he faced Sunday.

Stephenson, skating on the Capitals’ fourth line, found space on the left wing and ripped a wrist shot into the top-right corner of the net. It was Stephenson’s third goal in three games after he scored just twice in the first 49 games of his career. It was also the Capitals’ first goal against Fleury in 134 minutes 53 seconds, going back to Game 6 of last spring’s playoff series.

The Capitals lost the early lead before Niskanen nudged them ahead again in the second, then lost that lead when Golden Knights winger Reilly Smith scored a power-play goal later in the period. That tie lasted just 52 seconds into the third as rookie defenseman Christian Djoos threaded a pass through the zone and to a wide-open Nicklas Backstrom on the back post. But Vegas’s third game-tying goal came midway through the third when Smith snapped a shot past Grubauer.

The Capitals and Golden Knights clashed Sunday as very different franchises going in the very same direction this season. The Golden Knights are playing without the burden of expectations in their first year of existence. The expectations for these Capitals — with early playoff exits in the rearview and talks of their closing window never far away — will continue to swell as the playoffs near.

And, with Tuch’s late goal, the Golden Knights emerged from those 60 minutes as the better first-place team.

“I thought that we played well enough to at least get a point there, and we didn’t,” Capitals Coach Barry Trotz said before offering the realization that many teams have come to in the past four months. “That’s sort of the story of Vegas.”