ARLINGTON, Texas – Mark Calo-oy eventually had to save Yuriorkis Gamboa from himself Saturday night.

The veteran referee understandably stopped Gamboa’s dangerously one-sided bout against Isaac Cruz once the Mexican lightweight contender dropped Gamboa for the fourth time in as many rounds on the Errol Spence Jr.-Yordenis Ugas undercard at AT&T Stadium. Calo-oy stepped between them and wrapped his arms around Gamboa after he fell into the ropes following Cruz’s vicious left-right combination in the fifth round.

The ropes held up Cuba's Gamboa after he took those two shots, which counted as a knockdown. The official time of the stoppage was 1:32 of the fifth round in their scheduled 10-round, 135-pound bout.

Mexico City’s Cruz (23-2-1, 16 KOs) impressed against an aged former champion in his first fight since Gervonta Davis defeated him by unanimous decision in their 12-rounder December 5 at Staples Center in Los Angeles. The 40-year-old Gamboa (30-5, 18 KOs) lost a third straight fight and was knocked out for the fourth time in his 13-year pro career.

In the round before their fight ended, Cruz clipped Gamboa with a left hook that sent him to one knee with about 30 seconds to go in the fourth round. That marked the third straight round in which Gamboa hit the canvas.

Cruz caught Gamboa with a flush left hook that knocked him to the canvas less than five seconds into the third round.

After getting rocked in a completely one-sided first round, Gamboa began letting his hands go and traded with Cruz early in the second round.

Gamboa took Cruz’s power well for the rest of the second round, until Cruz crushed him with a right uppercut toward the end of it. That led to Cruz connecting with a right-left combination that sent Gamboa to one knee.

He popped right up to his feet, but he still seemed stunned when he walked back to his corner.

Almost as soon as their fight started, Cruz nailed Gamboa with a left hook that made Gamboa take a couple of awkward steps. Gamboa held enough to survive that early onslaught, but soon walked into more trouble.

In the middle minute of the first round, Cruz caught Gamboa with another flush left hook and an overhand right. With about 20 seconds to go in the first round, Cruz rocked Gamboa with another overhand right that knocked him into the ropes.

Gamboa held enough, though, to survive that troublesome first round.

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