ANAHEIM, Calif. — With one swing of the bat, Shohei Ohtani made the Yankees and Gerrit Cole pay for their mistakes in a 3-2 loss at Angel Stadium.

It not only led to their fourth loss in five games, the defeat also dropped the Yankees’ lead over the second-place Rays to just six games — the lowest it has been since June 3 — as they get ready for a three-game series in St. Petersburg, Fla., starting on Friday.

Asked about the team’s play in August, when the Yankees went 10-18 and had their worst month since going 9-19 in September 1991, Isiah Kiner-Falefa called it “brutal.’’

“I think all of us in here are not happy about the last month,” said Kiner-Falefa, whose error on a routine grounder by Mike Trout in the sixth inning helped set up Ohtani’s home run. “It’s a long season. Hopefully we can rebound. It might be a wake-up call for us.”

The Yankees seemingly had the Angels just where they wanted them heading into the bottom of the sixth.

They had scored the game’s first runs in the fifth to give Cole a two-run lead, looking for their second straight win.

But it went sideways quickly, starting with a delay to the start of the inning because of a fan running onto the field.

Josh Donaldson made a throwing error on a hard grounder by David Fletcher, sending Fletcher to second with one out in the inning.

Kiner-Falefa then booted Trout’s grounder to bring up Ohtani with two on and one out.

“No excuses,’’ Kiner-Falefa said. “It’s a play that needs to be made in a big spot and it cost us the game.”

Ohtani then took Cole deep for a three-run shot, his 30th of the season, to give the Angels the lead.

“It was the worst fastball of the night in a terrible spot,’’ Cole said of the pitch. “I tried to go away. It was a bad miss.”

The Yankees didn’t threaten after scoring two in the fifth until Aaron Judge led off the ninth against Jimmy Herget with a walk. With Giancarlo Stanton at the plate, Judge stole second before Stanton walked.

Donaldson struck out, and Gleyber Torres, who doubled in a run earlier, also whiffed.

Oswaldo Cabrera, pinch-hitting for Jose Trevino, grounded out to end it.

Aaron Boone lamented having used Tim Locastro as a pinch-runner for DJ LeMahieu in the eighth, saying he should have waited to see if LeMahieu got to second before subbing LeMahieu, since it forced Anthony Rizzo — who wasn’t in the lineup — to take over at first base after Locastro was stranded at first.

Rizzo never got to the plate and the Yankees had to go with the rookie Cabrera.

With the loss, the Yankees dropped a series to the fourth-place Angels after splitting a four-game set with the last-place A’s in Oakland.

The Yankees were mostly shut down by left-hander Patrick Sandoval.

Donaldson led off the fourth with a double down the left-field line and moved to third on a wild pitch with Torres at the plate.

Torres, slumping badly in the second half, came through with a double to the gap in right-center to score Donaldson and give the Yankees their first lead.

A fly ball to right sent Torres to third and Aaron Hicks drove him in with a sacrifice fly to left to make it 2-0.

Cole, who had given up more than one run just once in his previous four starts, got some help from the Yankees’ defense early on.

Hicks made a nice catch at the track in center field on a deep fly ball by Ohtani with one on and one out in the bottom of the first.

Kiner-Falefa then made a good play on a hard grounder by Luis Rengifo to end the inning.

The Yankees also turned a pair of double plays behind Cole in the first five innings.

But that stellar defense failed them in the sixth, and the Yankees may now find themselves in a race for the division title.

“It all comes down to how we answer,’’ Kiner-Falefa said. “We’ve just got to play better.”