Before the bottom of the 12th inning of last night’s game between the Charleston RiverDogs, the Yankees’ Low-A affiliate, and the Greenville Drive, Slade Heathcott was having a dreadful night.

The Yankees’ top pick in last year’s First-Year Player Draft, and the fourth-best prospect in the Yankees system, according to Baseball America, stepped to the plate with a runner on and two outs in a 1-1 game. He had been up five times previously – and struck out three of them.

But with one swing of the bat, Heathcott’s long night ended in an instant, as he hit a two-run home run and gave the RiverDogs a 3-1 win. It was the athletic outfielder from Texarkana, Texas, who is hitting .260 with 26 RBI and 13 stolen bases in 70 games with Charleston.

tbontemps@nypost.com