The 34-year-old Serbian had gone down twice and won only one round on one of the three judges’ scorecards. Then his fortune turned on a dime.

Kalajdzic came back to drop Gvozdyk twice and score a seventh-round knockout in the scheduled 10-round light heavyweight bout on the Zuffa Boxing 2 card Sunday at Meta Apex in Las Vegas.

“I was trying to find myself and trying to find my rhythm,” Kalajdzic told The Ring of his win over Gvozdyk. “I was taking my time and trying to figure myself out. Once I figured myself out, found my distance and started landing my jab, I knew I could hurt him. It was just getting to that point.”

He entered the contest 17 months after his last bout, a spirited unanimous decision defeat to David Morrell in 2024. For much of the bout Sunday, Kalajdzic (30-3, 22 KOs) felt like a fighter who was shaking off the cobwebs.

Gvozdyk (21-3, 17 KOs) didn’t help matters, as he surprised Kalajdzic with his aggressiveness to start the fight. The Ukrainian drew first blood when he knocked Kalajdzic down with a straight right hand in the first round. Kalajdzic touched the canvas again late in the fourth round when he sank into the ropes after a body shot, which referee Ray Corona ruled a knockdown.

“It's different when you fight under the lights,” Kalajdzic said. The small gloves, the timing, everything [is different]. In the first round, I got knocked down, and I calmed myself down. Then he started hitting me to the body in the fourth round.

"I wasn't hurt. I was just trying to slow things down and find my rhythm and slow the fight down, and find myself and find my punches, because nothing was working for me.”

Kalajdzic, 34, felt the tide start to turn in the sixth round, when he began to find a home for his straight right hand. Knowing a potential decision victory was long out the window, his coach, Rick Sabatini Caronongan, made sure his fighter knew what it was going to take to pull off the comeback victory.

“I only have four rounds left, and my coach gave me some motivation to believe in my punch that I couldn't really find my range [with],” Kalajdzic said. [Gvozdyk] was a little awkward, but my coach told me to believe in myself and let my hands go. Stop reaching in, find my distance, use a jab and follow up with the right hand.”

The momentum Kalajdzic felt he had built in the sixth round started to mount in the seventh. He started to bring the fight to Gvozdyk and began to routinely find a home for his jab and straight right hand. Kalajdzic couldn’t miss with the latter punch, and Gvozdyk started to breathe heavily and show signs of wearing down.

With 40 seconds left in the round, Kalajdzic dropped the former light heavyweight champion with yet another straight right hand.

“I was like, ‘Finally, the tide has turned. I got him now.’” Kalajdzic said. “I was telling myself, ‘I got to go in and finish him now.’”

Gvozdyk, 38, went after Kalajdzic despite being on unsteady legs. Kalajdzic landed a straight right hand to the body, then slightly slid back before connecting with one more jab and one last straight right that sent Gvozdyk crumbling to the canvas, far more hurt than when he was knocked down 20 seconds earlier.

He rose to his feet at a count of four, but immediately fell backward into his own corner, and Corona stopped the fight.

“The loss to Morrell, a [17-month] layoff, and then another loss would have set me back. Having a [17-month] layoff coming off a loss, it was just hard. Having this long layoff, then losing to find another top guy would have set me back big time.”

The win was Kalajdzic’s first in nearly two years. He stopped Sullivan Barrera in 10 rounds in March 2024.

Kalajdzic had dealt with numerous bouts of inactivity in his career. His layoff before facing Gvozdyk was the third-longest of his career, as he struggled with injuries and finding an opponent.

He was asked what he's hoping for the rest of this year.

“If not a big fight, just staying active with Zuffa,“ he said. “Try to fight in the next four or five months. I had too many layoffs in my career. Time is ticking.”