The American looked completely out of his depth against the Olympic champion, constantly hammered by Harrison's straight left hand.

Middleton, who appeared flabby at a weight of 224lbs, took a count of eight with just 15 seconds of the first round remaining.

A series of punches, including a left to the temple, put the 33-year-old down and referee Dave Parris decided to stop the contest when he arose.

The loser had already suffered a bloody nose and looked puffy around the face after less than three minutes of action.

Middleton's record drops to eight wins, 10 defeats with one no-contest.

The win will do little to appease sceptics of Harrison, although he looked competent enough with what little he had to do.

He looked confident at his weight of 250lbs and certainly seems to have retained the speed and boxing skill that he showed at Sydney.

The 29-year-old expects to fight again in the next two to three months.