Boxer Amir Khan drove dangerously when he accelerated through a red light and knocked down a pedestrian on a pelican crossing, a court has heard.
Mr Hatton suffered a broken leg in the collision on 2 March 2006
Jurors heard his high-performance BMW 6 series car reached 47mph as he overtook vehicles in the wrong lane just before traffic lights in Bolton town centre.
The pedestrian, Geoffrey Hatton, 55, told Bolton Crown Court he heard a "screaming engine" prior to the crash.
Mr Khan, 20, of Lostock, near Bolton, denies dangerous driving.
Mr Hatton, a foundry worker from Bolton, suffered a broken leg in the crash in Bradshawgate on 2 March 2006.
He had been walking to a local pub with a work colleague after finishing his shift.
Mr Hatton told the jury he heard his friend shout at him as he crossed the road and said he panicked as he thought a car was coming.
"I heard a screaming engine and the next thing I knew I was on the floor shouting 'I've lost my leg'," he added.
Mr Alaric Bassano, prosecuting, told the court Mr Khan was "well in excess of the speed limit" as he accelerated towards the junction with Great Moor Street during afternoon rush hour traffic.
Amir Khan denies dangerous driving
He said the carriageway was divided into two lanes and that Mr Khan - the reigning Commonwealth lightweight champion - wrongly overtook two vehicles in a right-turn only lane as he drove straight-on through the red light.
Mr Bassano added: "As he did so some pedestrians were on the pelican crossing.
"One of the pedestrians, the last one to cross, was Geoffrey Hatton - he was in the carriageway as the defendant was driving through the junction.
"He evidently panicked and he turned back towards the pavement.
"He moved into the defendant's line of traffic and the defendant's vehicle hit him.
"It was the cumulative effect of three factors taken together which rendered the defendant's driving dangerous - speed, overtaking in the wrong lane and driving through a red light," he added.
The incident was captured on CCTV and the footage shown to the jury on Tuesday.
Mr Hatton told the court he had thought it was safe to cross and that he had not been aware of any oncoming traffic.
The court was told that Mr Khan remained at the scene and was arrested and interviewed by police three months later, when he made no comment.
The trial was adjourned until Wednesday.