ST. PETERSBURG, Fla. — Slade Heathcott has had more than his share of problems in his short career, but Monday night, he saved the Yankees.

All this, after he saved himself.

No. 72, who came into the game as a defensive replacement in the bottom of the eighth, blasted a go-ahead three-run home run with two outs in the ninth off Brad Boxberger to lift the Yankees to an incredible 4-1 win over the Rays at Tropicana Field.

It was Heathcott’s first Yankees at-bat since May 27. The home run came on the first pitch, but that is just part of the outfielder’s story.

In this ninth inning, Alex Rodriguez came through when the Yankees needed him most, doubling home Brett Gardner with two outs to tie the game at 1-1.

Clearly, there still is some Pinstripe magic left.

Gardner walked to start the two-out rally for the Yankees, who did not get a hit off Rays starter Erasmo Ramirez until Carlos Beltran’s leadoff single in the eighth.

Heathcott’s home run, his second in 18 major league at-bats, was an opposite-field shot, into the first row of the left-field stands.

In spring training, Heathcott told The Post this was the year he was going to stop making excuses in his career.

“It’s time I take control of my life and my game,’’ he said.

Heathcott overcame alcohol problems early in his career, but the 2009 No. 1 pick kept running into injuries that slowed his progress. After being called up in May, a lingering quad injury damaged his season.

Despite all the best intentions, Heathcott was not able to keep his spring promise. He was still making excuses about his game down at Triple-A Scranton/Wilkes-Barre.

He was falling into an old trap.

He was losing the battle.

“I caught myself in Scranton getting back into that mindset,’’ Heathcott told me at his locker Monday night in a quiet moment. “I started struggling, started trying to find the easy way out and blame everybody else, and about three weeks ago I said to myself, ‘I can’t get back into this, regardless if this is good or bad, this is on me.’

“I only succeed if I want to, and making excuses and blaming everybody else doesn’t allow me to do that.’’

Everyone saw the home run and Heathcott sprinting around the bases, clapping as he rounded third, while teammates bounded out of the third base dugout to join him in celebration after he crossed the plate.

But this game-winner had its beginnings weeks ago, when Heathcott took control and stopped playing the blame game.

That is a testament to how far he has come as a player and a person, and it’s the greatest lesson young players have to learn.

“It’s a constant battle every day to be locked in,’’ Heathcott said.

“I play this game to win, I hate losing and I don’t like doing bad and most of all … is to help my team. That’s what it’s all about.

“This game is a battle for everyone, no one is really ever healthy, everybody is banged up,’’ added the lefty batter, who hit only two home runs in Triple-A this season and turns 25 at the end of the month.

“Part of maturing is learning how to play being banged-up and playing smart. I think this year I made a big step in that direction.’’

Heathcott has taken the biggest of steps, and his teammates are happy for him.

“It’s a moment he will never forget,’’ Rodriguez said. “What a story.’’

On the way out the clubhouse door, Rodriguez added one more comment.

“Our young players have energized us. Our farm system has been lifesavers for us. Every single one of these kids have come up and contributed. They come up well-schooled and with the right attitude.’’

An attitude that really kicked in for Heathcott just a few weeks ago.

Zachary Slade Heathcott has learned the biggest lesson of all for ballplayers.

No excuses.