Joe Calzaghe defied injury to produce one of the greatest performances of all time by a British boxer and unify the world super-middleweight titles in Manchester.

Calzaghe annihilated America's IBF champion and supposed next big thing Jeff Lacy, flooring him for the first time in his career and claiming every round on all three judges' scorecards.

Calzaghe's mesmerising display was put into context by Lacy's venerable trainer Dan Birmingham, who said: ''I have never seen a better performance by any fighter, anywhere in the world.''

It was all the more remarkable given a serious left wrist problem, which Calzaghe revealed had almost forced him to pull out of the fight three weeks ago.

Calzaghe said: ''It was 50-50. I spoke to Frank Warren, who said if you pull out now you'll never fight Lacy and the Americans won't be interested.

''I had five days off and knocked my main sparring on the head. My dad sat me down and persuaded me to listen and said 'you're going to destroy this guy'.''

Calzaghe, whose desire had been questioned when he pulled out of the original November date after breaking his hand in a routine defence against Evans Ashira, clutched an ice pack again.

But the pain proved well worth it as the 33-year-old Welshman laid claim to total dominance of the 12-stone division nine years and 18 defences after beating Chris Eubank to become WBO champion.

Lacy, also unbeaten, five years younger and rated by many good judges as the coming force of the sport, had been widely tipped to steal Calzaghe's crown on his own way to greatness.

Instead he was left bloodied, battered and floored for the first time in his career in the final round as Calzaghe's whirlwind assault raged from the first minute to the very last.

The final scorecards of 119-107 (twice) and 119-105 underlined Calzaghe's dominance. Only a late points deduction prevented him from claiming a complete shut-out.

Lacy, who required stitches around both eyes after the fight and also appeared to have broken his nose, said: ''He fought a perfect fight tonight.''

It was a performance so spell-binding it threatened to eclipse the greatest of British fight nights and announced Calzaghe - now unbeaten in 41 fights - as a true superstar.

A cracking right-hand counter-punch early in the first round set the tone for the fight with Lacy, already seeping blood from his nose, looking bemused and one-dimensional.

The Floridian simply had no answer to Calzaghe's devastating hand-speed and the beautifully paced assault continued in front of an exhilarated MEN Arena crowd of over 16,000.

Lacy's left eye was so badly bloodied by the end of the fourth it required the attention of the ringside doctor, and his desperation to get back into the fight played right into Calzaghe's hands.

Lacy may be nicknamed 'Left Hook' for his supposedly fearful shot which had helped lay out 17 of his victims, but even when he landed his trademark blow Calzaghe contemptuously flapped it away