Wayne McCullough stayed on course for a world title shot, but only after struggling to a split points decision over veteran Juan Polo Perez in Corpus Christie, Texas.

McCullough, the WBC's number one challenger, is chasing a shot at Mexico's super-bantamweight champion Erik Morales later in the year, but will have to improve after his 10-round encounter with the Colombian.

Perez, stopped in two rounds by WBO featherweight champion Prince Naseem Hamed in 1995, shocked McCullough with his early assaults and the judges' scoring could hardly have been closer with two voting for McCullough, 95-94, and one for the Colombian, 95-94.

Former world super flyweight champion Perez was expected to offer little threat to McCullough, but the former bantamweight title holder finished with a cut at the top of his head after the gruelling contest.

Perez edged the opening rounds with his movement and solid jab frustrating the Las Vagas-based Belfast man. But McCullough gradually found the target by the fifth round.

They provided some exciting exchanges in the second half of the non-title bout, with Perez countering the persistent volley of blows from McCullough.

Having been warned for low blows, 27-year-old McCullough was deducted a point in the ninth, which placed the contest on a knife edge.

But McCullough responded in the 10th with some furious assaults and his work-rate may well have given him the edge.