Michael Conforto of the Mets strikes out during the ninth inning against...

Michael Conforto of the Mets strikes out during the ninth inning against the Nationals during the Mets' home opener at Citi Field on Thursday. Credit: Jim McIsaac

Playing like a team that arrived in New York in the wee hours and barely slept before a day game, the Mets lost to the Nationals, 4-0, in their home opener Thursday at Citi Field.

Manager Mickey Callaway didn’t blame the Mets’ brutal travel schedule, including a 3 a.m. arrival delayed by postgame random drug tests in Miami on Wednesday night, preferring to credit Nationals righthander Stephen Strasburg.

Unlike Saturday in D.C., when a hypothetical duel between Noah Syndergaard and Strasburg turned into an 11-8 mess of a Mets win, this one lived up to the hype. Neither almost-ace allowed a hit until the fifth inning — the kind of battle that’s easy to imagine highlighting a long October series between these teams.

“I thought it was good energy,” Callaway said. “I think you have to give credit to their pitcher. Great pitcher, and he had really good stuff today. He was executing pitches at the bottom of the zone, keeping us off-kilter, and they just beat us. I thought our starter pitched a heck of a game as well.”

The no-hit drama ended before it really had a chance to start when Wilson Ramos led off the bottom of the fifth with a laced single past a diving Anthony Rendon into leftfield. Syndergaard’s no-no became a no-go minutes later when Victor Robles led off the sixth with a homer to left-center.

Strasburg allowed three hits, struck out nine and walked one in 6 2⁄3 innings. “When a pitcher is on, that makes it tough,” Callaway said.

Robinson Cano added: “I saw the same guy I always see — guys missing his pitches. A guy throwing the ball wherever he wants.”

Brandon Nimmo, who went 0-for-3 and is hitting .087 with 14 strikeouts in 23 at-bats, wasn’t as impressed.

“I think we missed a lot of good pitches,” he said. “I know for me personally there were some good pitches that I missed.”

Syndergaard was nearly Strasburg’s equal. He allowed two runs and one hit, Robles’ homer, in six innings. The Nats’ other run came in the second, when Syndergaard walked two and threw a wild pitch to set up Wilmer Difo’s safety squeeze bunt.

One area in which Syndergaard fell short of his counterpart: efficiency. He dealt with a high pitch count most of his outing, including a 19-pitch perfect fifth inning.

Callaway praised Syndergaard’s curveball usage. Syndergaard said that was key because he didn’t have a sharp slider, which was a problem for him last week, too.

“Slider really is not quite where I want it yet,” he said. “It’s encouraging to know that when my slider isn’t working, I can go to my curveball. Curveball was really good today. Even the one Robles hit out was a really good pitch. It was a good outing, but overall we got beat. We got to tip our hat to Strasburg.”

Washington’s bullpen, the worst in baseball the first week of the season (11.02 ERA), finished off Strasburg’s gem with 2 1⁄3 one-hit innings.

The Mets had their chances. In the fifth, they had two on and one out against Strasburg, but Juan Lagares and Syndergaard struck out swinging. In the seventh, Jeff McNeil and Amed Rosario hit two-out singles, but a managerial chess match — the Mets subbed Dominic Smith for Lagares, the Nationals brought in lefthander Matt Grace and the Mets countered with J.D. Davis for Smith — didn’t end in the Mets’ favor. It resulted in the Grace-Davis matchup Callaway wanted, but Davis struck out looking.

Seth Lugo and Tim Peterson combined to allow the Nats’ two runs in the ninth inning. Lugo, who has been ill and has pitched in four of the Mets’ seven games, has a 12.27 ERA.

“I think he’s going to be fine,” Callaway said. “He just didn’t have it.”

Whether it was because of a lack of sleep or Strasburg or both, what started as a buzzy, ceremonial day turned into a dud for the Mets.

“One game,” Cano said, “isn’t going to take us down.”

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