The 39-year-old grew into the match-up against his rival, 14 years his junior, and began to land some heavy blows.

As his dominance grew in the fourth round, he struck his opponent’s body with a huge left hook, which sent Gaballo to the covers. While he was able to recover before the 10 count he immediately needed to take a knee for further recovery and the ref waved off the fight.

Donaire’s liver punch inflicted only Gaballo’s second defeat of his career, while he moves onto a 42-6 record, and added his 28th knockout.

“I've been in this game for such a long time and I've had so many fights, I didn't think I was going to have to feel him out. But he came out differently than I thought he would. He tried to nullify my left hook, but I just had to have no mercy,” said Donaire, reported BoxingScene.com.

"My wife and my dad were telling me to go to the body. I had to set it up by bouncing up and down to open up that shot. I was throwing the right hand in the earlier rounds and then he didn't expect the left hook to the body.”

Donaire praised his opponent’s attempts to carry on despite the fierce punch he delivered to win the fight.

"I thought he was going to get up because I know he has a lot of heart, but that was a tremendous punch that landed. I just told him after the fight not to be down. Because he's a great fighter. I had trouble figuring him out and I'm here to help him with anything he needs for the rest of his career,” he said.

Next up for WBC champion Donaire could be a unification fight with Japan’s Nayao Inoue.

"It's my team's job to work on the rematch with Nayao Inoue. I believe my team is going to make it happen,” said Donaire.