Miami’s Jose Reyes, left, greets teammate Giancarlo Stanton after the latter’s solo home run in the seventh inning. Stanton homered in all three games of the series in Washington. (Toni L. Sandys/The Washington Post)

What a stinker!

The Nationals were so flat Sunday they looked like they’d all been shut down. With the Marlins already ahead 6-0 in the fifth inning and the Nats still without a hit, one fan broke the gorgeous sunny afternoon silence, yelling, “Wake up!”

Michael Morse immediately got a single, breaking up Ricky Nolasco’s no-hitter. But a double-play grounder ended the inning and sent the game back into its balmy breezy mood, as if a spring training game had broken out with 24,396 spectators. When Davey Johnson started resting regulars in an 8-0 loss, you swore you were in Viera, Fla.

“Ain’t much to say about that one, so . . . ” said Johnson, attempting, unsuccessfully, to negotiate the first eight-word news conference in baseball history.

Actually, this dud by the Nats served a purpose. You thought: “What’s going on here? Who’d watch this trash?” Then you realize that it’s what passed for big league ball for most of the years when D.C. had a team from 1901 right up until mighty recently.

“That’s maybe how it used to be,” Jayson Werth said. “Not anymore.”

Now, a lousy game is so out of character with the whole season that it shows how easy it is to be spoiled by winning baseball. Now, the Nats lead the majors in walk-off wins (19), including one less than 24 hours earlier when Werth tied Saturday’s Nats comeback in the bottom of the ninth with a homer after a 153-minute rain delay.

Now, even when they get stomped, the Nats still have baseball’s best record by 21 / 2 games over Cincinnati, which could lead to home-field advantage if they make the League Championship Series. And they lead the NL East by 51 / 2 games over Atlanta. The Braves are hot, winning seven of 10. But the Nats have been slightly hotter. When this homestand began, their lead was five games.

Check back next Sunday night, after the Nats finish a six-game road trip with three showdown games in Atlanta, to see how much, if any, of the buzz has been killed.

“We’ve got a lot of big games coming down the stretch. It’s going to be up to us. It’s not going to be easy,” said Werth, hitting .308 and flourishing as a leadoff hitter in what has emerged as one of baseball’s best second-half power-hitting lineups with four hitters who’ve had 30-homer seasons, two more who’ve had 20-homer years and another, Bryce Harper, who has 18 bombs as a 19-year-old rookie.

“We need to play good baseball and be the same team we’ve been all year,” Werth said. At least, after this laugher, the Nats should arrive in New York chuckling. Their seven rookies — yes, it’s the annual hazing trip — dressed up as the U.S. women’s gymnastics team.

The team the Nats “have been all year” is a club that does amazing things almost routinely. How different are expectations now? Trailing 8-0 in the eighth, much of the crowd — 99 percent probably praying that their DVRs had recorded Robert Griffin III’s debut properly — was still around, starting a rally chant. Hey, the Marlins lost a flyball in the sun. Isn’t that all it takes for a Nats comeback, just a crack in the door? No, of course not. But old assumptions have been slain — with lots of reason.

From 1901 until last week, no major league team in Washington history had hit more than four home runs in a home game. Then, on Tuesday, the Nats hit six. I apologized to family and friends when we attended Wednesday’s game: “After 111 years, we’re one day late.” Except that we weren’t. The Nats hit six home runs again on Wednesday, too.

In this 8-3 homestand alone, the Nats beat the contending Cardinals by a combined 18-1 in back-to-back games and, in all, won three of four. Next, they swept a four-game series from the Cubs so one-sidedly — including 15 homers — that the Chicago manager called it “men against boys.” On Thursday, for extra entertainment value, the Nats men and Cubs boys had two bench-clearing barn dances with four ejections plus Nats third base coach Bo Porter inviting the whole Cubs dugout to waltz with him personally.

In their previous 11 games before Sunday, the Nats had hit 30 homers, doubled the score on their foes (84-42), batted .341 as a team and .344 with men in scoring position. In that span, Harper and Adam LaRoche each hit six homers. Gio Gonzalez, pushing for 20 wins and a spot in the Cy Young Award race, had 16 scoreless innings in back-to-back wins.

So, why did the Nats get four-hit by a .500 pitcher like Nolasco (12-12)? Okay, he also shut them out 12 days ago; maybe he owns ’em. But it’s also possible the Nats were just exhausted. The thought of continuing to run around the bases was just too much for them. So, working hypothesis: on Sunday, they rested.

If the Nats lose all their remaining 22 games (they’d still have 86 wins which, at the moment, looks like it might make a wild-card spot), we’ll rework that theory a tad. But, balancing this one game against the 139 before it, we’ll call it an anomaly for now.

For a century it’s been said that you see something new and memorable in every big league game. This one had a chance to break the rule and be utterly worthless. Then, in the seventh inning, Rob Brantly hit a line drive over Harper’s head in center field. A base runner sped around the bases. Then everybody stopped. The ball had disappeared.

Harper threw up his hands, the universal sign for “ground-rule double” or “what the hell just happened?!” Beside the 402-foot sign, the ball found a hole under the fence just big enough to stage its escape; it was going, gone, the first ball to burrow out of the park.

Like all the rest of us who finally left this game, it was free at last.

For previous columns by Thomas Boswell, visit­boswell.