The midfielder, who denies a charge of assault and a public order offence, clashed with the 16-year-old student near his home in Manchester, northwest England, last year, Trafford Magistrates' Court was told.

Keane, 33, was walking his dogs when the boy rode past on a moped with a friend and beeped his horn to acknowledge the star, the court was told.

As the moped passed, Keane -- who was then injured -- swung out with his walking stick, prompting the 16-year-old, who was not named in court, to turn around and make a crude hand gesture at the footballer.

A few weeks later in September 2004, the pair were visiting a friend near Keane's home when they were approached by the sportsman, the boy said in a videotaped interview to police shown to the court in place of direct testimony.

The teenager told police he was sitting on the moped when he noticed Keane walking towards him.

"I felt a bit like, 'God, what's going to happen now'," the boy said.

"Then he (Keane) said: 'Did you call me a wanker? Why did you do that?"'

The teenager said he replied: "Because you nearly hit me; you swung for me with your walking stick.

"He walked up to me and I'm not sure what he said next; he was being a bit aggressive.

"The next thing he did was swing at my face with his right fist. He said, 'That's nearly hitting you'. I flinched backwards."

Keane also grabbed the boy round the neck, the court was told.

The trial was expected to last two days.