Amir Khan secures hard-fought win over Mexican Julio Diaz

Amir Khan demonstrated new-found maturity and tremendous powers of recuperation to come through a stormy encounter with Julio Diaz in Sheffield.

In his first bout in Britain for two years, the Bolton fighter was well on top until the fourth round, when he was floored by the Mexican's left hook.

But Khan, 26, recovered well and stood up to some enormous punches late on.

The judges scored it unanimously in favour of Khan, who again showed why he is Britain's most exciting fighter.

However, he will come in for plenty of criticism, from those who believe he still has leaky defences, an iffy chin and a seemingly unbreakable habit of being drawn into a war almost every time he fights.

"Julio gave me a tough fight," Khan said. "He caught me with a shot, though I was off-balance.

"He was tough and never took a step back. That was one of my hardest fights."

Khan's victory - in the 143lb catchweight contest - means he could be one win away from another world title shot, although it may also be his last fight in the UK.

Khan lost his WBA and IBF light-welterweight titles to Lamont Peterson in 2011 before losing his next fight to Danny Garcia last July.

However, Khan got back to winning ways with a straightforward victory over Carlos Molina last December.

Garcia successfully defended his WBC and WBA belts against fellow American Zab Judah later on Saturday evening, winning a unanimous points decision in Brooklyn, while Peterson faces Lucas Matthysse in May.

The victors of those contests are expected to fight each other, with the winner of that bout scheduled to fight Khan in December.

Diaz, a 33-year-old two-time lightweight world champion, arrived with 14 years of experience in the professional ranks and was coming off a good draw with American prospect Shawn Porter.

After being outworked by Khan in the first round, Diaz found his feet in the second, landing with a couple of flashing left hooks.

But Khan refused to be drawn into a war and, while Diaz landed with a couple of solid right hands in the third, it was probably the Englishman's round again.

Diaz floored Khan with a left hook two minutes into the fourth and, although Khan gathered his senses quickly, it was a 10-8 round for the visitor.

Khan boxed sensibly in the fifth, circling away from Diaz's dangerous left hook, staying at range and winning the round with his jab.

Feeding off the calming influence of American trainer Virgil Hunter, Khan controlled proceedings off the back foot in the sixth, but there were some furious exchanges in the seventh as Khan suddenly decided to stand and trade.

He stood up to a crashing left hook in the eighth but was stiffened by a right to the temple midway through the round as Diaz came on strong.

Khan got on his bike in the ninth, landing with some snappy combinations from long range, but the 10th round was Diaz's, the veteran wobbling Khan with another crackerjack left hook.

Khan was in desperate trouble in the 11th but somehow managed to stay on his feet and, despite Khan still shipping big shots in the final round, Diaz was unable to finish the job.

With the judges unanimously handing the result to Khan with scorecards of 114-113, 115-113, 115-112, he improves to 28 wins from 31 professional encounters, while Diaz now has 40 wins, eight defeats and one draw.