Lightweight title defence: Khan is taken all the way but shows his sheer class

Tricky opponent gets best out of Amir as he goes full 12 rounds for first time

Amir Khan came through the most rigorous examination of his professional career with distinction last night, successfully defending his Commonwealth lightweight title against a fight-hardened challenger in Gairy St Clair with an overwhelming points victory. In fact, it was a complete shut-out, all three British judges giving him the maximum points, 120-108, which meant he had won every round.

Indeed he had, with a stylishly controlled display of boxing that was a measure of the improvement he has made since winning the Olympic silver medal in 2004. The last time Khan was in the ring was on his 21st birthday in December. Last night was St Clair's 33rd birthday and it was Khan who duly blew out the candles on the Ghanaian-born Aussie's intended celebrations.

"I kept coming back," said Khan. "I learned more in there than winning in the first round. He was coming and coming, so I had to pace myself and it went well. I've done 12 rounds against a world-class opponent and I'm sure this will take me a long way. This was a good learning fight."

No one expected Khan to make short work of the 5ft 4in St Clair and this was never going to be another 72-second blitz. The former IBF super-featherweight champion boasts a granite chin and he soaked up everything Khan threw at him, moving forward menacingly though with little effect.

Khan had to survive the first cut eyebrow of his career, caused by an apparent clash of heads in the fifth, and worryingly St Clair found his way through with several wild right hands that, had they been delivered by a heavier puncher, could have been catastrophic.

Khan simply zipped through the rounds, going the full championship distance for the first time, watched from the ringside by one of his closest sporting buddies, Andy Murray, who applauded boxing's equivalent of a straight-sets victory. The former world champion Naseem Hamed was there too and must have been deeply impressed by the manner of Khan's victory.

St Clair seemed dazzled from the start as Khan peppered him with straight shots. All he did in the initial stages was crouch, bob and weave. Khan did everything but put him away but this fight was exactly what he needed at this stage of his career.

St Clair was no mug. Barry McGuigan said he was "flabbergasted" that Khan's management had chosen St Clair as a substitute for his original Danish opponent. "If I was managing him I'm not sure I would have made the same move at this stage," he said.

As Khan said, St Clair had not come all the way from New South Wales to fall down. The gnomish old pro had never been stopped or dropped in 46 contests and has taken it on the chin from former world champions Vivian Harris and Diego Corrales without flinching.

Khan had promised a change of tack, to punch and move differently, and creditably he managed to curb his built-in instinct for full-steam-ahead demolition. He also said he needed an opponent to make him think, and St Clair did. The little man had come up the hard way in the gyms of New York and such is his pedigree that you have to rate this as a potentially world-class performance from Khan in only his 16th fight.

Now he has come of age Khan is adapting impressively to manhood, developing more muscle in his physique and maturing in his personality. He is also moving into the Beckham league as a commercial attraction, and a major announcement about his future in this field will be made by top agency M&C Saatchi in London tomorrow.

The crowd also witnessed an intriguing slice of boxing history when three brothers, Rotherham-born Michael Walsh, 23, and twins Liam and Ryan, 21, made their pro debuts on the same bill, all winning their fights on early stoppages. The most famous – or perhaps infamous – occasion when three brothers appeared in the same ring on the same night was at the Royal Albert Hall back in 1951. Their names were Reggie, Ronnie and Charlie Kray.

Ross Minter failed to emulate his father Alan in winning a world title – albeit the lightly regarded World Boxing Union (WBU) welterweight belt – when he was stopped in nine rounds by the holder, Michael Jennings of Chorley.

Minter, 29, put up brave resistance in a bout brimful of pulsating exchanges, finishing with a cut head and blood pouring from his left ear. He was floored twice, in the fourth and again in the ninth, by a left-right combination which sent him down for a count of eight. He was on his feet and battled on but referee Mickey Vann stepped in, just as the towel fluttered in Minter's corner, one second from the end of the round.