Amir upbeat after Preston flaw show

These championships were to have been held in the local Larches Social Club but such is Khan's pulling power that they were moved to the Guildhall, where all 2,800 seats were sold long before fight night.

It will be of concern to Khan's extended family - they occupied two entire rows of ringside seats - and potential professional backers that this most amiable of young sportsmen has attracted a confrontational element to support him.

They loudly jeered the introduction of Khan's first-round opponent, Craig Watson, and master of ceremonies Russ Arrowsmith threatened to call off Khan's second bout of the evening when a bank of his supporters began taunting those of ring rival Liam Dorrian with the kind of overt aggression that had security personnel running to form a wall between the verbally warring factions. This was Khan's first fight at light-welterweight - he is unlikely to make the 60kilo lightweight limit again - and Watson's extra strength was revealed in dramatic fashion midway during the fourth and final round when a stunning left dumped the championship favourite on his backside.

Khan said: "I went in with my hands low and the guy caught me flush on the chin. But I recovered straight away and went straight back in."

Khan had already done enough to secure victory and the points margin of 21-9 was a fair reflection of his overall superiority.

But it was a different matter against Dorrian, last year's beaten ABA lightweight semi-finalist. Khan was warned for wrestling his opponent to the floor and Dorrian had points deducted for going in with his head low. Khan, lacking discipline, then left himself open to a straight right on the nose that caused blood to flow in the first round. Then, intent on protecting a clear points lead in the last round, Khan received another warning for dancing around the ring out of reach of Dorrian. The verdict of 23-4 in Khan's favour was generous and he conceded: "I will learn from my mistakes."

Khan now heads to the North-West finals in Liverpool on 18 February, but onward progression to the National ABA Finals in London on 18 March might no longer be a formality.