The Cardinals’ Matt Holliday doubles past a diving Anthony Rendon in the first inning. The Nationals were down, 3-0, before sending a man to the plate Thursday. (John McDonnell/The Washington Post)

The Washington Nationals have more than five months, starting immediately, to shake the perception that clings to them now, after the 8-0, self-inflicted humiliation they suffered Thursday night against the St. Louis Cardinals. The season remains young, but already they have enhanced a reputation that sprouted last year. When faced with a lesser opponent, they dominate. When they encounter the kind of team they aspire to be, they wilt.

The Nationals had another chance Thursday night at Nationals Park to vanquish both an elite foe and the perception that they’re a team unable to beat baseball’s best. They responded with a shoddy defense that committed four errors and left starter Taylor Jordan helpless. They answered with an offense that Cardinals ace Adam Wainwright rendered inert.

Afterward, two players said, Manager Matt Williams expressed his anger at the performance. None shared what Williams had said to them. “That’s for me and my team and nobody else’s business,” Williams said. “Regarding the game, probably the worst one we’ve played.”

The Nationals trailed by three runs before they even took their first turn at-bat, committed defensive miscues that ranged from disheartening to comedic and produced two hits — the first a single in the second by Ian Desmond that bounced off home plate, the second a single from Adam LaRoche with two outs in the ninth.

The Nationals entered this season with the unapologetic expectation of reclaiming the National League East. They have looked capable when the New York Mets and Miami Marlins hit the schedule. In the six games against the Atlanta Braves and Thursday’s meltdown against the Cardinals, they have committed 14 of their MLB-high 20 errors while getting outscored 40-16.

The Nationals are hitting well—for now. When will the dreadful fielding and injury woes catch up? The Post’s Adam Kilgore discusses the early highs and lows for the team. (Post Sports Live/The Washington Post)

“The numbers are what they are,” said Desmond, whose two errors boosted his total to seven, tops in the majors. “It doesn’t worry me because I believe in this team and I believe in what we can do. But believing in yourself only goes so far. You’ve got to go out and execute. If we don’t start doing it soon, we’re going to end up in the bottom. And that’s not acceptable for any of us in here.”

Since opening day 2013, the Nationals have gone 8-30 against the Braves, Cardinals and Los Angeles Dodgers, the NL’s reigning division champs. It may seem unfair to conflate last year’s results (7-24) with this year’s outcomes (1-6). And the Nationals have three games this weekend with their best three starters taking the mound, not to mention the 143 games to follow, to flip their narrative.

“They can certainly put a lot of this to rest in the next three,” Williams said. “But we’ve got to play well to beat this club.”

The Nationals’ play against top competition suggests elite opponents change them. The Nationals entered Thursday leading the NL in runs per game. And yet in seven games against the Braves and Cardinals, they have scored more than three runs just once. In nine games against lower-rung teams, the Nationals have committed six errors.

“I’m not alarmed,” Williams said. “I’m alarmed, if anything, about us. If we take care of things, then we’ve got a chance every day. But there’s been some games when we haven’t done that. That’s what we’ll strive to do.”

The low point came Thursday night. The first batter of the game reached on a Desmond error. The Cardinals scored three runs in the inning and hopped on Wainwright’s broad shoulders. The miscues piled up until Jayson Werth lost a liner in the lights, the ball sailing past him.

“It’s nice to beat the good teams,” LaRoche said. “It kind of reinforces how good a team we are. Everyone still believes that. It’s just time to start showing it.”

Including Game 5 of the 2012 NLDS, the Cardinals have won eight straight against the Nationals. On Friday night, the Nationals will try to break their skid against right-hander Michael Wacha, who last September came within Ryan Zimmerman’s chopper over the mound with two outs in the ninth inning of dealing the Nationals a no-hitter. On Thursday night, Wainwright shut them down for a two-hit complete game.

“We handed that to him on a tee — me especially,” Desmond said. “Can’t give that pitcher of that caliber any kind of leeway or show any kinks in the armor. Right off the bat, they just stepped on our throat.”

For the seventh time in their first 16 games, the Nationals surrendered at least three runs in the first inning. After Desmond booted Matt Carpenter’s leadoff grounder, Jordan collected a dribbler and, after a struggle to remove the ball from his mitt, threw late to first. Desmond committed another error in the fourth, this one on a throw that bounced maybe 10 feet short of first base.

“The first ball of the game, you boot it, that doesn’t set the tone,” Desmond said. “If I ever want to be the captain of this team — and I do — I’m going to have to be better than that. I’ve been in some dark places defensively, and this is right there with them. You’ve got to work through it.”

The night’s most darkly comic moment came in the sixth. Catcher Jose Lobaton called for one pitch, Treinen threw another and the ball skipped to the backstop. “I was waiting for a slider,” Lobaton said. “Thank God he didn’t throw me one in the middle. It would’ve killed me.”

Treinen scampered to cover the plate and pointed at third base, where two Cardinals base runners had converged as the ball caromed straight to Lobaton. Lobaton instead flipped errantly to Treinen, and as the ball trickled across the infield grass, every Cardinals runner retreated to a base. One pitch later, Matt Adams smoked a two-RBI single to center, and the stadium organist did well to refrain from “Yakety Sax.”

By the ninth, random shouts echoed off swaths of empty seats.

“It’s one game,” Williams said. “And it’s not easy for them to play it, and it’s not easy for us to experience it. But what do you do now? You have one choice, and that’s to concentrate on tomorrow.”