Mandalay Bay, Las Vegas - Some observers felt undefeated mandatory challenger Shohjahon Ergashev (23-1, 20 KOs) would have more than enough to unseat Subriel Matias from the IBF junior welterweight championship.

At the start of the fight, that appeared to be the case when Ergashev was unloading with big punches in the first two rounds.

Matias began to work his way into the fight in the third round, as his hands began to let loose with hard combinations on the inside.

The same pattern continued in the fourth and fifth, with Matias battering Ergashev around the ring with hard combinations. Ergashev, who got stunned more than once from Matias' incoming bombs, was holding on for dear life at times.

At the start of the sixth round Ergashev refused to get up from his stool to continue the fight.

Matias improved to 20-1 with 20 KOs in his first title defense.

According to Ergashev's statements in the corner, he had a pain in his leg and was unable to move around the ring. It wasn't immediately clear what the issue was.

“I felt a pain and wasn’t able to move,” Ergashev said. “I just couldn’t move around the ring in the last two rounds. Once I got hurt, I wasn’t able to display any offense, and I couldn’t use my defense because once my legs gave out on me, I couldn’t stick to the game plan. I wasn’t able to move around the ring and use angles like I did in the first two rounds.”

Matías connected on 108 of 317 total punches for a 34% clip, compared to 44 of 235 and 19% for Ergashev, with 26 of Ergashev's total connects in the first two rounds. Over five rounds, Matías landed 71 power punches and 37 jabs to complete the dominant performance.