The Capitals’ Keith Aucoin and the Rangers’ Chris Kreider catch a few moments of rest in the second overtime period last night.

The Capitals’ Keith Aucoin and the Rangers’ Chris Kreider catch a few moments of rest in the second overtime period last night.

Rangers 2, Capitals 1: When the powers that be were establishing the culture of professional hockey, we’re pretty sure no one ever said “Hey, let’s play two.” But that’s just about what last night’s marathon match between the Capitals and Rangers wound up being, as the game stayed tied at one goal a piece deep into the third overtime period. After each team scored a goal in the second period, the game became an epic contest of endurance and accuracy. The third period expired, sending the Caps to their fifth overtime in 10 games this postseason. And there are no shootouts in the playoffs; they’ll just keep tacking on extra frames until someone scores. No one did in the first overtime, nor the second, with both Braden Holtby and New York goaltender Henrik Lundqvist making save after save (with plenty of assist on both sides from the crossbar). But it was in the 115th minute of play, well after midnight, that the Rangers’ Marian Gaborik finally broke the stalemate.

“Whenever you lose in overtime it sucks, but when you lose in triple overtime it’s even worse,” Caps defenseman Karl Alzner told the Post after the game. No kidding. The Capitals will try to undo the sting after resting up today and tomorrow and resuming the series on Saturday.

Nationals 5, Diamondbacks 4: For a while, it looked that despite Bryce Harper’s three hits (including two doubles), the Nationals were still on pace to lose their sixth straight game. Harper showed some more flashes of that brilliance the Nats expect; his first double was just inches from being his first major-league home run. But all night, the Nationals found themselves looking up at the Diamondbacks, who scored four runs in Edwin Jackson’s six-inning start. The bullpen held Arizona steady, but the Diamondbacks’ relief was just as tough. That is, until J.J. Putz came on for the save in the ninth. With Arizona leading 4-3, Harper roped his second double of the night. The next two batters made out, but with the Nationals down to their last chance, it was Ian Desmond, of all people, who launched the game-winning home run, ending the Nats’ slide and making the Diamondbacks’ closer look like, well, you know.