ST. LOUIS -- There was a warm reunion in the underbelly of Busch Stadium earlier this weekend, as Gerrit Cole and Jordan Montgomery hugged and renewed acquaintances, the ex-teammates catching up on the latest chatter in their respective clubhouses.

They parted wishing each other good luck in the future, except for the obvious. Though Cole posted a strong effort before being named to the American League All-Star team, Montgomery was a touch better, holding his former club hitless into the sixth inning as the Yanks wrapped their road trip with a 5-1 loss to the Cardinals on Sunday afternoon.

“Today, the story was Montgomery. I got outpitched,” Cole said. “He was outstanding today, moving the ball well. … When he’s on, he’s really tough. That was what we had to deal with today. Unfortunately I wasn’t good enough to be able to hold them down quite enough.”

Brendan Donovan hit a late homer off reliever Jimmy Cordero, helping St. Louis pull away.

It was an eventful 3-3 trip for the Yanks, destined to be remembered most for Domingo Germán’s perfect game on Wednesday against the Athletics -- the 24th in AL/NL history, and the fourth by a Yankee.

“Guys are grinding,” said manager Aaron Boone, who was ejected in the third inning for arguing balls and strikes. “We’re making some progress in some areas, and hopefully getting closer and closer to being more and more healthy.

“We did some good things, but you always want to win series. We weren’t able to pull this series off, which would have been a nice little run of series victories for us. But it’s on to the next one.”

Cole had to grind to limit the damage by the Cards, permitting run-scoring hits to Jordan Walker and Andrew Knizner in the fourth inning. Cole scattered six hits to go with two walks and five strikeouts.

“I thought it was a solid day,” Cole said. “I made a lot of good pitches -- a couple of mistakes.”

Montgomery had no such laments, having held the Yankees hitless until Gleyber Torres’ sixth-inning double. Montgomery said that when he returned to his locker, a text message from Cole was waiting on his cell phone: an animated GIF of a cowboy tipping his cap.

“Gerrit’s been a great mentor,” Montgomery said. “Him and [Corey] Kluber sat me down and helped me with my routine. They got it down to a minute for my pregame, game-day routine. He’s just been great. We stay in contact. He’s a great friend.”

A popular figure in the Bombers’ clubhouse who was dealt to St. Louis last August in exchange for outfielder Harrison Bader, Montgomery permitted just one other hit: Jake Bauers’ booming run-scoring double in the seventh.

“I think he threw five shutout against us last year [on Aug. 6, 2022], too,” Cole said. “He’s had some big games for us. I specifically remember Game [4] of the [AL Division Series] in 2020, his first postseason start. That was a big one for him. I was with him in the tunnel. He gave us a good shot to win against the Rays.”

“I’ve known Montgomery for a long time, and I think he’s pitching really well,” Torres said. “I thought we had a really good plan of attack, but his command was really good. He pitched really well.”

By the time Montgomery accepted a warm ovation from the third sellout crowd of the weekend, Boone had already seen four innings from his office in the visiting clubhouse.

Ejected by home-plate umpire Dan Merzel for arguing a high 3-1 pitch to DJ LeMahieu that was called a strike, Boone accepted his fifth ejection of the season, and his first since May 25 vs. Baltimore.

“I think Dan is a really good young umpire. I really do,” Boone said. “I’ve had some good interactions with him. I think that the rope and the leash was very short, though. I had a real problem with that. The sensitivity on that and the quick throw-out is just brutal. It was ridiculous. You’ve got to have thicker skin than that.”