Gavin Rees retained his European lightweight title Saturday when challenger Derry Mathews was forced to retire in the fourth round with a broken nose in Newport, Wales.

Referee John Keane declared the bout a technical draw after local favorite Rees, 31, accidentally butted his opponent flush in the face — with the back of his head — while attempting to throw an uppercut from close range.

With blood pouring from Mathews’ injured nose, which gave him trouble breathing, the ringside doctor ruled he was unable to continue. It meant that what had been shaping up to be a challenging first defense for the titleholder from Newbridge ended in unsatisfactory fashion.

A rematch between the Brits before the end of the year is now in the cards.

“It was building into a good fight to be honest, and it’s a shame for the fans. I don’t know if I’ve got a mandatory defense now but, if not, he can definitely have another shot,” said Rees (35-1-1, 16 knockouts). “We had a bit of a chess match out there. Next time we’ll know what it’s all about.”

Matthews (29-5-1, 15 KOs) was understandably distraught at being robbed of a chance to make his mark on the division. But the Englishman insisted Rees was not to blame.

“I’m absolutely devastated. I’ve worked so hard for the fight, and I know Gavin has too. But these things happen in life, and you’ve just got to get on with it,” said the 28-year-old from Liverpool, Merseyside. “As soon as my nose went, I knew it was broken, and I was swallowing blood. I hope Gavin can give me the return and we can get it back on.”