BASEL, Switzerland — Undefeated Arthur Abraham stopped Wayne Elcock in the fifth round to retain his IBF middleweight title Saturday night.

The Armenia-born German knocked down Elcock in the second round and then again in the fifth. The referee stopped the fight after Abraham landed a flurry of punches to the Englishman's head.

Abraham, 25-0 with 20 knockouts, has been eyeing a unification bout against either Jermain Taylor or Kelly Pavlik next year in the United States.

The 27-year-old Abraham's only scare came in the third round, when an accidental head-butt opened up a cut above his right eye. But Elcock (18-3), was unable to take advantage.

"I'm happy that I won tonight," Abraham said. "It wasn't an easy fight."

An undercard bout between heavyweights Danny Williams and Oleg Platov ended in a no-contest after a deep cut above Platov's left eye caused the fight to be stopped in the fourth round. Williams was denied the victory because the cut was ruled to have been caused by an accidental head-butt in the second round.

"That's the rule, so you cannot disagree," Williams said.

The 34-year-old Englishman is 37-6. Platov, from the Ukraine, is 26-1.