For five rounds Saturday night, Oleksandr Gvozdyk didn’t at all resemble the unbeaten WBC light heavyweight champion who knocked out Adonis Stevenson four years ago.

In the sixth round, however, Ukraine’s Gvozdyk made up for his slow start and bombarded Ricards Bolotniks with power punches that eventually made the Latvian veteran take a knee. A battered, bloodied Bolotniks beat referee Celestino Ruiz’s count, but Ruiz wisely stopped their 10-round light heavyweight fight on the Canelo Alvarez-John Ryder undercard at Akron Stadium in Zapopan, Mexico.

The opener of DAZN’s five-fight pay-per-view show was officially halted at 1:53 of sixth round.

The 36-year-old Gvozdyk (19-1, 15 KOs) fought for just the second time against Bolotniks (19-7-1, 8 KOs) since he decided to end his retirement late last year.

Gvozdyk won his first fight back from more than a three-year layoff February 11 in Pomona, California. He out-pointed Mexican journeyman Josue Obando (20-35-2, 15 KOs) unanimously in their six-round cruiserweight contest.

Gvozdyk retired after his punishing 10th-round knockout loss to Russian knockout artist Artur Beterbiev (19-0, 19 KOs) in October 2019 at Temple University’s Liacouras Center in Philadelphia.

On Saturday night, a right hand by Gvozdyk knocked out Bolotniks’ mouthpiece with just under 1:40 to go in the sixth round. Another right hand made Bolotniks stumble backward about 10 seconds later.

Gvozdyk’s left hook made Bolotniks take a knee with 1:17 to go in the sixth round. He got up before Ruiz counted to 10, but Ruiz didn’t think Bolotniks was fit to continue and stopped the fight.

Gvodzyk’s right uppercut backed up Bolotniks about 15 seconds into the sixth round.

Gvozdyk mostly landed jabs during the fifth round, but he couldn’t keep Bolotniks from coming forward. Bolotniks’ right hand connected with just over a minute on the clock in the fifth round.

Bolotniks backed Gvozdyk and snapped back his head with a left hook 50 seconds into the fourth round. Bolotniks had a lot of success with his left hook to that point in their fight.

Gvozdyk’s right uppercut backed up Bolotniks several seconds after the midway mark of the third round. A left hook by Bolotniks caught Gvozdyk about 55 seconds into the third round.

Bolotniks’ left hook landed with just under 15 seconds remaining in the second round. Gvozdyk connected with a right uppercut with just under 1:40 on the clock in the second round.

Bolotniks landed a right hand just after the halfway point of the first round. Gvozdyk threw a mostly ineffective jab during the opening round.

Keith Idec is a senior writer/columnist for BoxingScene.com. He can be reached on Twitter @Idecboxing.