A semi-professional footballer killed a teenager with a single blow to the head, a jury was told.

Daniel Sheriffe, 24, who plays as a winger for Bradford Park Avenue, struck 17-year-old Jose Augusto with such force he was knocked down and struck his head so hard on the ground he fractured the base of his skull, Leeds Crown Court was told yesterday. Prosecutor Paul Worsley, QC, said the footballer delivered the blow "with all the force he could muster."

Mr Augusto, who was 5ft 8ins tall and weighed ten stone, suffered swelling to the brain and irreversible brain damage. He never regained consciousness and died in hospital four days later.

The court heard the footballer, who has pleaded not guilty to manslaughter, had been to the Town House nightclub in Leeds city centre for a friend's wake on the night of the incident on August 27 last year.

Mr Worsley said that the victim, who was from Angola in Africa and had been staying with his sister in Leeds, had been out drinking with two friends when he was attacked just before 2.30am.

He told the jury there was no question of the blow being struck in self-defence.

"Jose Augusto struck no blow to anyone before he was attacked, nor did he threaten violence to anyone. All he was doing was chatting with some girls who did not seem to be interested in him," said Mr Worsley.

"The prosecution does not allege that Daniel Sheriffe intended to kill Jose Augusto. The charge is manslaughter, that he deliberately and unlawfully delivered a blow which caused him to fall back and hit his head on the ground." He said there was no question of the blow being accidental and added that Sheriffe was a semi-professional footballer.

He told the jury: "You may think he was fit and athletic."

Mr Worsley said a witness heard the defendant say "Come on then" and in one quick movement he swivelled from the hip with a punch with his fist clenched like a boxer "striking his head with a horrible sound." He said another witness, trainee nurse Christina Barton, saw the victim fall backwards and his head hit the ground with such a loud crack "everyone went quiet for a few seconds, then started screaming."

Mr Worsley told the jury there was no dispute someone was guilty of manslaughter but the question was who did it. He said Sheriffe, of Hamilton Avenue, Chapeltown, Leeds, denied he was the person who struck the fatal blow and had nothing to do with the attack.

But he said two separate witnesses had identified Sheriffe as the attacker.

He said Sheriffe had claimed to police that he saw Mr Augusto lying on the ground after leaving the club. He said he had not seen or spoken to him before.

But he sa id CCTV footage showed the soccer player leaving a club five minutes before Mr Augusto was struck.

Mr Worsley said Home Office pathologist Professor Christopher Milroy concluded death was due to a head injury typical of a fall on to the back of the head. He also found bruising on the left side of the jaw consistent with a punch.

The jury was told that the first witness, Leroy Wright, picked out Sheriffe at a video identification procedure on September 15. Mr Wright said he saw Sheriffe punch a man once in the face. He told the jury: "He struck him one single blow with his hand. The man fell to the ground and there was a noise like a crack."

He described the man as 20-30 years old, of athletic build, with close-cropped black hair and wearing dark clothing.

A teenager told the court today he called an ambulance seconds after his friend was knocked to the ground by a punch on the jaw. Student Luis Antonio, 17, was out in Leeds with Mr Augusto on the night he died.

Mr Antonio said that Mr Augusto was threatening the girls but he did not believe he was serious and he did not touch them. But a man standing nearby took offence at Jose's behaviour.

"He pushed me out of the way, went over to Jose and punched him in the face. Jose fell backwards on the ground. There was blood and he wasn't moving."

The trial continues.