DIEGO PACHECO surged to an explosive victory on his UK debut dismantling Jack Cullen  then stopping him inside four rounds.

The Californian stepped into the main event slot at the M&S Bank Arena in Liverpool after an injury to hometown favorite Callum Smith prevented him from fighting on this bill.

And Pacheco lived up to the top billing with the impressive performance which moves him to 18-0, with Cullen becoming the 15th opponent vanquished inside the distance.

Cullen had started reasonably well, landing a few stiff jabs in the opening round but you got the sense that Pacheco was taking his time to have a good look at ‘Little Lever’s Meat Cleaver’.

Pacheco, still just 22 years old, started to go through the gears in the second round and was working well on the counter and dictating the distance with his feet.

He turned up the heat further in the third and two right uppercuts which landed flush were a sign of things to come from Pacheco, who was clearly now finding his range. And so it proved in the fourth when he landed a right hand on Cullen’s neck and then dropped him with the follow-up left hook to the body.

Cullen got to his feet but the writing was on the wall. Pacheco landed a double jab and then two thunderous right hands which left Cullen crumpled against the ropes and there was still time for a left hook on his way down as Steve Gray jumped in to stop the fight. The official time was 0:47 of round four.

Pacheco said: "I'm really happy with my performance. It was my job to deliver and I think I did that tonight.

“I felt the same as every fight. My job is to put on a great performance every time I step into the ring - it doesn’t matter where I am.

“He was really tough. I respect him for getting up but I knew I was going to take him out in that round, I wasn’t letting him get away from that.”

“I feel ready for anyone in my division and anybody in boxing. I’m super excited for the future and I’m ready for whatever is next.”

His promoter Eddie Hearn added: “After this we will continue to headline all over the world, particularly LA. 

“Tonight we lose one word: ‘prospect’ is gone. World-class star and a future world champion - that’s what Diego is.

“That was precise punching, hard punching, body punching. It was calmness in the ring. 

"At 17 he would hardly look at you but now he’s like a young lion. This is the future for Pacheco now, he’s still 22 but I think we’re very lucky to have him.”