Bryce Harper ambled out of the shower, sat at the chair in front of his locker with his shoulders hunched over. The 19-year-old slipped on jeans and a gray long-sleeve shirt, placed a knit beanie onto his head and white headphones around his neck, and slipped out.

The rest of the Washington Nationals lingered, some still dressing and others talking about Saturday’s exhausting 5-3 loss to the New York Yankees after 14 innings of back-and-forth baseball, replete with strategy, errors, strong pitching and a close play at the plate. Harper, however, wanted none of it.

“I don’t want to talk,” he said.

The teenage star whose ferocious swing can smash balls into upper decks had been humbled. He had just endured the worst day of his short major league career, an 0-for-7 performance with five frustrating strikeouts.

He made contact only twice in those seven trips to the plate. Yankees starter Andy Pettitte, 21 years Harper’s senior, pumped sliders low and Harper flailed. Yankee relievers did the same, exploiting the hole. Four of Harper’s five strikeouts were on sliders, most of them out of the strike zone.

With each passing at bat, Harper’s body language at the plate worsened. In his 10th inning at-bat against left-handed reliever Clay Rapada, Harper let loose. He struck out looking at a slider low and away, seemingly out of the strike zone. Harper slammed his bat into the ground, turned to home plate umpire Tim Timmons and barked at him.

“This is probably his first really tough game where he was chasing balls and over-anxious,” Manager Davey Johnson said. “That’s showing some of his inexperience. But, again, that’s young guys trying to do too much.”

This series was supposed to be a showcase of the first-place Nationals, the young squad with ascendant players such as Harper, threatening the blue-blood Yankees, who are also atop their division. The baseball world was curious to see how these Nationals would fare. In two tries, the Nationals have been competitive but haven’t capitalized as they’ve lost twice.

“Right now, obviously, they seem bad,” reliever Brad Lidge said. “These games are magnified.”

Starter Jordan Zimmermann pitched around defensive lapses and his own mistakes to hold the Yankees to three runs, two earned, through six innings. The Nationals’ bullpen did the rest, holding the Yankees hitless for seven innings. After Eric Chavez’s double gave the Yankees a 3-2 lead in the sixth, they managed no other hits until the 14th inning.

Ian Desmond, who almost didn’t play on Saturday because of an injury to his side, tied the game at 3 in the eighth inning with his 10th home run of the season, a solo shot to left field. After his first three at-bats, the knot in his side bugged him. “I hit the home run there and I wondered if there was anything there at all,” said the one-time leadoff hitter, now the Nationals’ second-best power hitter.

Then came a chance to pull ahead. Rookie first baseman Tyler Moore, inserted into the lineup over left-handed Adam LaRoche because of the left-handed Pettitte, drew a walk following Desmond’s home run. After Moore stole second, LaRoche, pinch-hitting for reliever Ross Detwiler, slapped an outside pitch to shallow right field.

The ball bounced once in front of DeWayne Wise, who had moved to right field just before LaRoche’s at-bat, and, with one step, slung it to catcher Russell Martin without a bounce. By then, Moore had rounded third and knew a tag was coming.

Moore awkwardly slid head-first — almost like a belly flop into a pool — and slid his left hand across the plate. Martin’s tag appeared to be a few inches too late, but Timmons called Moore out. “I thought I got in there,” Moore said.

Little happened until the 14th, when Lidge, the veteran reliever with 225 career saves who was making his second appearance in as many days, emerged from the bullpen. Jayson Nix reached on an infield single and stole second base. Derek Jeter then reached on a single. Finally, after Lidge struck out Curtis Granderson, Mark Teixeira smacked a double to right field that scored Nix and Jeter. Four batters, three hits and two runs, and the Yankees were ahead.

“I’m in a bit of bad luck right know where they’re kind of hitting them where they ain’t,” Lidge said.

It was only fitting that the game would end with Harper. One slider from closer Rafael Soriano was enough to induce a groundout to second base. The Nationals had ruined their opportunities, and Harper was upset for having done the same. LaRoche approached Harper after the game and offered encouragement.

“It’s not the last time you’re going to have a bad game,” he told the rookie. “I’ve told him before, if you’re lucky, you’ll have lots of bad games because you’re playing for a long time. I said, ‘Shake it off and hurt them tomorrow.’ ”