It was called a ball.
"It was a curveball a really good pitch," Calhoun said. "It kind of froze me. I might have gotten a little lucky there. But that's the game, right?"
On the 2-2 pitch, Calhoun drilled a fastball over the fence in right.
"Just looking to put the ball in play," he said. "But he got a pitch out over the middle, and I put a good swing on it."
Asked if it was his first-ever walk-off homer, Calhoun said, "I had one in college summer ball year once way back."
The Bees jumped in front, 1-0, in the first inning when Ryan Langerhans led off with a double and Calhoun followed with a triple.
Oklahoma City broke through in the fifth on Jimmy Paredes' RBI double and designated hitter Fernando Martinez' two-run homer, making it 3-1.
Salt Lake's turn to rally came in the seventh, when Corey Aldridge singled and, with two out, Matt Long drilled a base hit to right.
With runners on first and third, the Bees' Ed Lucas hit a chopper toward first baseman Mike Hessman. Because he was holding Long on the bag, the ball just cleared Hessman's glove and rolled into the Salt Lake bullpen.
By the time rightfielder Brad Snyder got to the ball, Aldridge had scored and Long was rounding third base and being waved home by manager Keith Johnson.
The throw to the plate was late, meaning Lucas' two-run triple tied the game 3-3 and eventually sent it into extra innings.
"Our guys are doing a great job right now of battling," Johnson said. "Our bullpen put up some more zeros tonight. The guys battled back and Kole, you can't say enough about that."
Rockies 6, Owlz 5 • After claiming an early 4-0 lead, Orem lost at home to Grand Junction.
Chukars 6, Raptors 5 • Ogden fell on the road in a 15-inning duel.
Storylines Bees 4, RedHawks 3
R Kole Calhoun's solo homer with two out in the 10th inning gives Salt Lake its fifth straight victory.