ST. PETERSBURG, Fla. — The Yankees’ collapse hit a new low on Friday night, when they were blown out by the Rays, 9-0, and had to resort to using Marwin Gonzalez on the mound. 

After manager Aaron Boone said he hoped the unwelcome addition of a pennant race would bring out the best in his Yankees, they went out and played one of their worst games of the season. The Yankees’ slide continued, and their lead over the Rays dropped to five games — the lowest it has been since June 1 — and just four ahead in the loss column. 

“That’s an embarrassing loss,” Boone said. “Hopefully, it’s one of those rock-bottom things where you should be pissed off [and] embarrassed.” 

It was the Yankees’ fifth loss in their past six games — following a five-game winning streak — while Tampa Bay won its fourth straight. 

The Yankees’ offense was a no-show again as they were shut out for the sixth time in their past 25 games. And the lineup took another hit when Andrew Benintendi left with a right wrist injury. 

The bullpen was shoddy, as well, with Greg Weissert and Anthony Banda giving up three runs each before Gonzalez came on to get the final out in the bottom of the eighth. 

“We’re gonna see what this team’s made of,’’ Aaron Judge said. “No team has ever coasted into the postseason. We’ve got to go out and bring it every single day.” 

That didn’t happen Friday, as Boone and Judge acknowledged. 

“I do think the effort is there,’’ Boone said of his team, which went 0-for-7 with runners in scoring position and left 10 runners on base. 

“We’ve got to score,’’ Boone said. “We’re capable. We’re banged up, obviously, but that can’t be an excuse forever.” 

They wasted a fine pitching performance by Domingo German, who was done in by a pair of Josh Donaldson errors in the fourth and a two-run homer by Christian Bethancourt in the seventh. 

The Yankees threatened with two outs in the first, when Benintendi doubled and Giancarlo Stanton walked, but Donaldson struck out looking. 

With one out in the top of the third, DJ LeMahieu walked before Judge reached on a catcher’s interference after the Yankees challenged the initial call of a foul ball. 

Benintendi then was forced from the game with a right wrist injury and replaced by Oswaldo Cabrera. 

The Rays went ahead in the fourth thanks to a pair of errors by Donaldson. 

After jawing with left-hander Jeffrey Springs in the top of the fourth inning, Donaldson’s fielding error on a Harold Ramirez grounder got the Rays’ rally started in the bottom of the fourth. 

The next play, Donaldson’s throwing error on Randy Arozarena’s ground ball nearly scored a run, but Ramirez was thrown out at the plate by Cabrera from right field. 

Arozarena went to third on the play and scored on David Peralta’s single to center. 

Things got ugly in the bottom of the eighth, when the Yankees walked in a pair of runs before Banda drilled Ji-Man Choi with a pitch to load the bases again. That’s when Boone went to the mound with Gonzalez, who got Ramirez on a comebacker to finally end the six-run inning, as the surging Rays went on to win for the 10th time in 12 games. 

“I don’t pay attention to it,’’ Judge said of the Yankees’ disappearing lead. “The worst thing you can do is press. If we do what we need to do, have good at bats, command stuff on the mound, we’ll look up at the end of the year and be where we want to be in the standings.” 

For now, they still are. 

“We’re still in first place,” Judge said. “But I don’t want to hang my hat on that.” 

The Yankees’ lead could fall to three games by the end of the series if they don’t figure out a way to beat the Rays, who they will play five more times in the next nine games.