Kalajdzic trailed 60-52 on two cards and 59-53 on the third at the time of the stoppage in the opener of the main card of Zuffa Boxing 2 at Meta Apex Center in Las Vegas.

"The first five, six rounds, it was like I just started boxing," Kalajdzic said after the fight. "That's how I felt like, but thanks to my coach [and] my teammates, they still told me to trust myself, believe in myself, be patient, work behind the jab and the knockout came, they told me, if I landed that right correctly and throw it correctly, I was going to hurt him, and that's what happened."

Gvozdyk (21-3, 17 KOs) got off to a fast start, knocking Kalajdzic (30-3, 22 KOs) down in the first round with a straight right hand. Kalajdzic hit the canvas hard, but he rose to his feet on steady legs.

Gvozdyk stayed on the front foot and landed the cleaner, more effective shots throughout the fight. Kalajdzic had his moments when he was able to establish his jab and use his speed advantage, but it wasn’t enough to overcome the offensive attack of the Ukrainian. Gvozdyk, 38, continually made the Serbian pay when he was pulling straight back out of range.

In the fourth round, Gvozdyk again hurt Kalajdzic, who sank into the ropes after taking a body shot. Referee Ray Corona ruled it a knockdown. After the sixth round, Kalajdzic’s team implored him to dig deep.

Dig deep, he did.

Kalajdzic began to mount his rally early in the seventh round, when he connected with a straight right hand that stopped Gvozdyk in his tracks. Kalajdzic couldn’t miss with his straight right hand thereafter, and “The Nail” finally fell with under one minute left in the round.

Gvozdyk got to his feet on unsteady legs and was sent to the canvas again after another clean, straight right hand from Kalajdzic. After getting to his feet, Gvozdyk went stumbling back into a corner, and Corona called a halt to the fight.

The win was Kalajdzic’s first since 2024.

Here are the undercard results from earlier in the night.

10 rounds, 157-pound catchweight: Jalil Hackett (12-1, 9 KOs) def. Roberto Cruz (11-2, 7 KOs) by majority decision (97-93, 96-94, 95-95)

8 rounds, lightweight: Justin Viloria (12-0, 8 KOs) def. Oscar Perez (14-1-2, 7 KOs) by unanimous decision (79-73, 78-74, 77-75)

8 rounds, 150-pound catchweight: Damoni Cato-Cain (9-1-2, 7 KOs) def. Christian Morales (7-1, 7 KOs) by unanimous decision (80-72, 79-73, 77-75)

6 rounds, heavyweight: Damazion Vanhouter (11-0, 8 KOs) def. Julian Gomez (7-4, 2 KOs) by third-round TKO

6 rounds, cruiserweight: Jamar Talley (6-0, 5 KOs) def. Devonte Williams (13-4, 6 KOs) by second-round knockout