Skelton was forced to up the pace after collecting an early cut

In a torrid fight, Skelton put the 6ft 5in Australian-based Croatian on the floor with an uppercut in the first.

The Briton then had to up the pace after picking up a cut in round two.

And with his right eye closing Skelton went for broke, putting Mirovic down in the third and causing the challenger to throw in the towel after the fourth.

The Bedford heavyweight has now stopped 13 of his 14 opponents, winning his titles against Michael Sprott in April.

I do make these fights difficult for myself sometimes Matt Skelton

It was a brave, if far from convincing, performance from Skelton, who regularly left himself open to the challenger's swinging left hook.

However, a sustained attack in round four left the Australian champion refusing to come out for the fifth, despite the protestations of his trainer.

"I was really tired," said Skelton.

"What I'm disappointed about is that in the first couple of rounds I did what the team were asking but then my eye started to close.

"The corner told me I had a problem and I had to go out for the third round and try and stop him.

"I could see everything clearly but I was aware there was swelling on the eye and I didn't want the referee to stop it.

"We all knew that Mirovic would come to fight. I tried to work behind the jab and move and not get too involved but you want to fight.