Amir Khan was forced to clamber off the canvas and survive a ferocious five-round war before finally despatching Michael Gomez to retain his Commonwealth lightweight title in Birmingham.

Khan was briefly dropped by a crashing left hand from Gomez in round two as the heroic Manchester man made a mockery of pre-fight predictions that the Olympic silver medallist was in for an easy ride.

Gomez himself clawed his way off the canvas in the opening round and again early in the fifth before a huge right hand from Khan signalled the end. With Gomez sagging in the ropes, referee John Keane stepped in at two minutes 32 seconds of the fifth.

The high-octane war proved a valuable learning experience for Khan who had to deal with the commendable spirit of a former British super-featherweight champion seeking his last shot at glory on his 31st birthday.

But ultimately Khan kept his poise and showed strength and unerring accuracy as he held off his opponent to score his 18th professional win and move closer to his dream of a world title shot.

Gomez had always promised to make use his trademark ferocity to unsettle Khan and drag the Olympic silver medallist into the sort of war he had yet to encounter in his 17 professional fights to date.

But signs had suggested Gomez's best days were behind him and that he was far from the same fighter who stunned previously unbeaten Alex Arthur to score a career-best fifth round knockout victory in 2003.

Gomez came into this fight having lost three of his last six, including a bizarre mid-round retirement against Peter McDonagh in 2006, and a sixth-round stoppage by Carl Johanneson in October last year.

And Khan had rubbished Gomez's pre-fight taunts, insisting nothing would derail him from his stated intention to move into the world title picture and possibly a world title challenge to WBO champion Nate Campbell next year.

Recent, relatively straight-forward wins over Gairy St Clair and Martin Kristjansen had continued Khan's learning curve while continuing to underline that he still has a number of improvements to make.

Working with his new trainer Dean Powell, Khan pronounced himself fitter than ever ahead of his clash with Gomez.

But this did not look likely to be a fight to test his stamina as Khan came close to a first round win.

Starting behind a sharp left jab, Khan was soon pouring the punches through his opponent's porous guard and a scything combination ending in a big right hand dropped Gomez to the canvas.

It was all the Manchester man could do to simply survive the round but he showed commendable spirit to stay on his feet to hear the first bell and raced out for the second in sensational fashion.

Storming through Khan's sharp shots, Gomez slammed home a left hook to Khan's jaw which briefly dropped the Bolton man but Khan soon regrouped and a probing straight left soon had Gomez back in trouble.

It was proving to be every bit the big test Gomez had promised and despite being bloodied around his left eye the former British super-featherweight champion ploughed on in search of another knockdown blow.

Both men exchanged left hooks at the end of a fast and furious second and it was astonishing to see Gomez still standing after all the punishment he had taken.

With referee John Keane watching closely, Khan continued firing home relentlessly accurate right hands while Gomez, head down, sought to bull in close and regain the initiative.

Another left hook clattered home into Gomez's bloodied cheek but the challenger was still driving on and made it safely to the end of the third.

How Gomez stayed on his feet when he was driven from one side of the ring to the other by a series of Khan bombs early in round four almost defied belief.

But the Manchester boxer was still firing back enough to prevent Keane's intervention.

Khan dropped Gomez early in round five with a left to the body but Gomez got up and again came back.

A straight left caught Khan but Gomez's punches lacked their early bite and Khan was in total control.

A jolting right midway through the fifth battered Gomez back against the ropes and as Khan poured in bombs from either hand Keane wisely decided the Manchester man's astonishing challenge was finally over.