Luis Alberto Lopez needed to again cross the Atlantic Ocean if he wanted to remain a featherweight champion. And for the second time in six months, Lopez retained the IBF belt in the 126-pound division.

Lopez stopped Michael Conlan in Belfast, Northern Ireland, on Saturday with a thunderous right uppercut in the fifth round that put the Irish challenger on his back and prompted his corner to throw the towel to stop the bout before the referee could administer a 10-count.

"I wanted to come to Belfast so I can prove that I am a true champion," Lopez said through an interpreter in a postfight interview with BT Sport.

Conlan was down for a couple of minutes following the stoppage and received oxygen from the medical staff before he eventually sat up and returned to his corner. He stood in the middle of the ring and applauded Lopez as the result was announced inside the ring.

Lopez (28-2, 16 KOs) was making his first title defense of the IBF featherweight belt. Last December, Lopez fought Josh Warrington in Warrington's hometown of Leeds, England, and picked up a majority decision.

The scorecards weren't necessary on Saturday.

After Conlan used his southpaw jab and body work to keep Lopez at a distance, the tide shifted in the third round. Lopez caught Conlan with a right uppercut, the first punch in a flurry that appeared to hurt Conlan (18-2, 9 KOs), who retreated to the ropes and was able to survive the round.

But for the rest of the fight, Lopez was in command. Adam Booth, Conlan's trainer, expressed concern over Conlan's body language after the fourth round, in which Conlan was looking to tie up Lopez.

Conlan was unable to get back into the fight before Lopez landed the massive knockout.

"I'm more powerful than him," Lopez told BT Sport. "I'm stronger than him and had speed and great footwork."

It was Conlan's second attempt at a featherweight title. Last March, Leigh Wood stopped Conlan in the 12th round to retain the WBA belt.

Conlan defeated Miguel Marriaga, a journeyman contender, in August, to rebuild momentum following the loss to Wood.

Lopez was seen limping in the ring following the victory, and he told BT Sport that he was dealing with a leg issue in the locker room. However, the ailment didn't stop the 29-year-old from keeping his spot as one of the world's top featherweights.

Lamati seriously hurt: Featherweight contender Ludumo Lamati was taken out of the ring on a stretcher following his stoppage loss to Nick Ball on the Lopez-Conlan undercard. The bout was waived off in the 12th round by Lamati's corner after the South African fighter continued to sustain significant damage.

The Lopez-Conlan bout was delayed for several minutes as medical officials offered assistance to Lamati, and no update on his condition was immediately available.