Scott Harrison dominated the fight from start to finish

The fight went the distance but the Scot controlled the action from first bell to last.

Harrison's punching power constantly troubled McCullough in front of a hugely partisan crowd at the Braehead Arena in Glasgow.

The champion was the winner by scores of 119-109, 119-108 and 120-108.

Round by round: Harrison v McCullough

"Wayne is one of the best in the world. He kept coming back from my hard punches - I've got a lot of respect for him," said Harrison.

"But I used my jab and the angles, Basically I put the combinations together with speed and power."

He was better and stronger than I thought he'd be - that's why I couldn't mix it up Wayne McCullough

McCullough, 32, never managed to close the distance between him and the champion and was constantly hit by jabs and right hands.

"He was better and stronger than I thought he'd be - that's why I couldn't mix it up. He hurt me early on," said the Irishman.

"He's unbelievably strong. It wasn't a matter of size - it was strength. I could still jab with him but his strength is unbelievable."

Despite both men weighing in at the nine stone featherweight limit, Harrison looked the bigger man and his strength was, as McCullough admitted, one of the prevailing factors.

The Irishman showed great resilience, though, and managed to stay on his feet despite looking ready to hit the canvas in rounds six and eight.

Referee John Coyle almost stepped in to stop the contest on several occasions, but Harrison had to settle for a unanimous points victory.

Never floored or stopped in his 11-year career, McCullough was hurt on more occasions than during his fights with Prince Naseem Hamed or Erik Morales.

For Harrison, a fight with veteran American Johnny Tapia, who was ringside, beckons after a thoroughly impressive display which will have brought him international recognition with the fight being televised in America.

As for McCullough, the defeat, his fourth in 30 fights against 26 wins, may well spell the end of his chances at world class level.

The champion's record improves to 19 wins, with one defeat and one draw.

Scotland's Alex Arthur is British super featherweight champion

On the undercard, Scotland's Alex Arthur struggled before stopping South African Patrick Malinga in six rounds.

The British super featherweight champion was given a tough workout by Malinga, a noted puncher.

The visitor appeared to stun Arthur in the second round but failed to put the 24-year-old under sustained pressure thereafter.

By the sixth round, Malinga had tired severely and was wobbled badly by a right hand.

Following a long period of pressure on the ropes, the South African was rocked by another right hand, forcing the timely intervention of the referee.

Arthur improves his record to 15 wins, with 12 knockouts, while the loser suffered his fourth defeat in 18 fights.

Elsewhere, American Cory Spinks snatched the IBF world welterweight title from Michele Piccirillo in an unanimous point decision.

The 25-year-old son of former world heavyweight champion Leon Spinks led between two to six points in the scorecards of the three judges - two Americans and one Italian.

It was a reverse outcome of the first title fight here last April when the 33-year-old Italian boxer overcame Spinks on points.

Miguel Barrera stopped Roberto Leyva with a straight right to the body at 1:07 of the third round to retain his IBF mini-flyweight championship.

The fight was a rematch of a fight in which Barrera took the title from Leyva.