OAKLAND, Calif. — Imagine the embarrassment, showing up for the party of the summer with your ascot smudged, your monocle cracked and your white pants sporting a red-wine stain the size of an iguana.

Welcome to life as a Yankee right now.

This weekend’s “World Series preview” at Dodger Stadium, starting Friday night, naturally loses some of its shine when the Yankees come limping in, lugging a four-game losing streak and carrying more questions and doubts than a vegan at a barbecue festival.

On Thursday night, a lackluster-looking Yankees group suffered a 5-3 loss to the Athletics at Oakland Coliseum, their personal house of horrors (where they’re 7-21 in their last 28 games) thereby suffering their third sweep by an opponent this season and their first since they dropped a pair at Arizona on April 30 and May 1. This three-game visit to the East Bay went about as well as the three-hour tour run by the Skipper and Gilligan.

And now, the Dodgers, who at 85-44 own baseball’s best record.

“I think at the end of the day, you have to believe in yourselves,” said Masahiro Tanaka, the Yankees’ losing pitcher in Thursday’s game. “Just keep moving forward.”

“Just try to prepare really well,” Gleyber Torres said. “Tomorrow is another day.”

Tanaka and Torres personified the glass-half-full view of this lost stop. Both committed transgressions that led to the defeat. Yet Tanaka protected his team’s bullpen by gutting out six innings despite allowing five runs — it tells you plenty about the series that Tanaka pitched the best of any Yankees starter here — while Torres put up a monster night at the plate, homering twice, doubling and singling, to make up for a poor defensive play that hurt the Yankees in the critical third inning.

Indeed, the entire game might have looked a lot different had Didi Gregorius snared a Matt Olson grounder up the middle that went off the shortstop’s glove (it was scored as a single, and it advanced Matt Chapman to second) and had Torres completed a double play after recording the force at second on a Stephen Piscotty grounder. Instead, Torres threw the relay way too high, allowing Chapman — who had singled home Robbie Grossman from third base — to score a second run in the third.

“I think I got a little lazy and I didn’t prepare really well myself in that situation,” the sophomore Torres said. “I feel super bad for that.”

The Yankees’ non-Torres offense, meanwhile, generally made a hero out of a non-ace A’s starter for the third straight night. This time, former National and Red Tanner Roark lasted 6 ¹/₃ innings while allowing just two runs and seven hits, walking none and striking out seven. None of the current-day trio of Roark, Mike Fiers or Homer Bailey will be confused for Justin Verlander, Zack Greinke or Gerrit Cole, apparently unless they’re facing the Yankees here in Oaktown.

One specific silver lining beyond Torres that could turn into something far bigger: Aaron Judge registered another good night, going 2-for-3 with a single, double and walk. He has looked notably better at the plate for nearly a week now.

Now the Yankees, who at 83-46 still possess the American League’s best record and the second-best mark in all of baseball, take on the one team better than them, and let’s face it: There won’t be any shock if they depart Southern California after Sunday night’s game as the recipients of a second consecutive sweep. The Dodgers can look ridiculously good, particularly at Chavez Ravine, where they sport a 51-16 record.

“Over the course of a long season, you’re going to take one in the mouth,” manager Aaron Boone said, recycling one of his favored dog-days phrases. “We just got punched in the mouth here in Oakland.”

Can they clean up their act against the game’s finest? Ready or not, the Yankees must go to Hollywood. Do they look ready to you?