ATLANTA — It was an all too familiar sight, even though it felt like one that belonged to a different timeline.

The Mets offense was quiet, their defense suspect, and Atlanta feasted on a fill-in starter while ace Chris Sale came one out shy of a complete game, all to the tune of a 5-0 loss Wednesday night at a muggy Truist Park; they’ve now dropped a season-high five in a row.

It’s a time-worn dance performed by these two rivals, though this year, by nature of the Mets’ 45-29 record and Atlanta’s deep underperformance, it seemed like things would be different. Instead, the Mets go into Thursday trying to avert their second sweep in a row after not getting swept through the first 22 series of the year.

“We’ve kind of run into a rut here this past week,” said Paul Blackburn, who was pitching for an injured Kodai Senga and allowed four runs (three earned) and four hits with two walks and two strikeouts over 3 2⁄3 innings. At one point, “it felt like we were winning every single day. I think the biggest thing is keeping on that track — don’t get too high, don’t get too low, just keep pushing forward.”

This is, though, their first true test: Questions swirl about the state of their injury-battered rotation, and suddenly, that chokehold they have on the National League East doesn’t seem quite so secure, with the surging Phillies having won six of their last seven and now one game back in the standings.

And then, of course, there was Sale, who was indomitable, riding that low arm slot and nasty slider to 8 2⁄3 innings of shutout ball, with five hits, a walk and seven strikeouts. The Mets got just one runner into scoring position — Starling Marte in the first inning. It was the fifth time they’ve been shut out this season.

“You’ve got to give him credit,” Carlos Mendoza said of Sale. “Throughout the course of the year, you’re going to be facing guys like that, and today he was on, so you’ve got to tip your cap.”

Francisco Lindor, Juan Soto, Pete Alonso and Brandon Nimmo went 1-for-15 with a walk and six strikeouts. Sale was lifted for Raisel Iglesias after Nimmo’s two-out single in the ninth; he’d thrown 116 pitches.

Blackburn kicked things off in inauspicious fashion, giving up a first-pitch, 419-foot bomb to leadoff batter Ronald Acuna Jr. Alex Verdugo singled and Austin Riley walked, both advancing into scoring position when Matt Olson hit a grounder to first that was stopped by a diving Alonso. Blackburn’s curveball to Marcell Ozuna bounced in front of the plate and Luis Torrens illegally used his mask to corral it — a rare catcher’s balk that forced the lead runner home. Ozuna then skied a sacrifice fly to center to give Atlanta a 3-0 first-inning lead.

“I took my mask off and I just touched the ball with my mask,” Torrens said through an interpreter. “It just ended up happening and it shouldn’t have happened.”

Blackburn allowed a one-out double to Ozzie Albies in the third; Albies eventually advanced to third and scored on Jose Butto’s wild pitch. Ty Adcock let up a solo homer to Olson in the seventh to make it 5-0.

The Mets used five pitchers in the second of 13 straight games, including eight more games against Atlanta and the Phillies. They did it after losing Senga to a hamstring injury last week, Tylor Megill to an elbow sprain this week, and as Frankie Montas continues to flounder in his rehab outings. They’ll also need a spot starter Friday to go up against probable pitcher Zack Wheeler in Philadelphia.

Wednesday, in what presumably is his final rehab outing, Montas allowed five runs on seven hits with a walk and two strikeouts over five innings, and threw 80 pitches, 47 for strikes.

In six minor-league outings since returning from a lat injury, he compiled a 12.05 ERA, leading Mendoza to question whether the righthander would be activated when his rehab clock expires on Sunday. After that, they’ll have 48 hours to add Montas, who signed a two-year, $34 million contract this offseason.

“This is the time of year that we’re going through it,” Lindor said. “Every team goes through it and as a team, we’ve got to continue to push each other . . . dig deep and continue to climb. At the end of the day, everybody here wants it. It’s a long year. We’re going to deal with adversity, put our heads down and work as hard as [we] can to get back to the winning side and then don’t look back.”

Brett Baty was kept out of the starting lineup for the second game in a row after exiting with a groin injury Sunday. He wasn’t available off the bench Wednesday and an IL stint is possible if he doesn’t make progress Thursday, Mendoza said.