Galal Yafai picked apart Moises Calleros before he eventually dropped and stopped him Saturday night at O2 Arena in London.

The British southpaw sent the Mexican veteran to the canvas barely 30 seconds into the fourth round. Calleros, a former world title challenger, got up in time, but referee Kiernan McCann halted their scheduled 10-round super flyweight fight 44 seconds into the fourth round on the Anthony Joshua-Jermaine Franklin undercard.

Birmingham’s Yafai, 2021 Olympic gold medalist, improved to 4-0 and recorded his third knockout. Monterrey’s Calleros (36-11-1, 19 KOs) lost inside the distance for the fifth time in his 14-year pro career.

Yafai wobbled Calleros with a right hook less than 30 seconds into the fourth round. The southpaw connected with several more power punches, including a left hand that sent Calleros to his gloves and knees with 2:27 on the clock in the fourth round.

Calleros got up in time to beat the count, but McCann still stopped the fight.

A patient Yafai continued to pick apart Calleros throughout the third round.

Yafai’s left hand wobbled Calleros just before the midway mark of the second round. Yafai’s straight left snapped back Calleros’ head about 30 seconds into the second round.

Yafai caught Calleros with a right hook and then a straight left hand with just under a minute remaining in the opening round. The faster, more accurate Yafai was sharp throughout that one-sided first round.

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