John Nerney was giving evidence to the Central Criminal Court in the trial of an internet and call shop owner, charged with murdering a customer over a 70c debt.
Zhen Dong Zhao (36), a Chinese man with an address at Jervis Street, Dublin, has pleaded not guilty to murdering Finglas man Noel Fegan on May 20, 2011.
The alleged attack took place outside e-Times on Dublin's Wellington Quay. Mr Fegan (40) had gone into the shop to phone his daughter from whom he had received a 'Call Me' text.
Mr Nerney said he was waiting for a bus outside the internet cafe at about 4pm.
"The accused threw the victim out of the shop and the victim fell on the ground," he said. "He kicked him a few times in the back and head."
He said the victim was on all fours and trying to crawl away when the accused paused.
"I thought he'd stopped, but he kicked him fairly firmly in the skull," he continued, comparing its force with that of a long-distance kick in football.
Mr Nerney said the victim then vomited. He said the accused didn't seem enraged during the assault, and gave him a two-fingered gesture afterwards.
Mr Nerney told Brendan Grehan, defending, that he did not see the accused throw the victim out of the shop. "I got the impression he was forcefully removed from the shop," he said. The trial has already heard that Zhen accepts that he kicked the deceased after Mr Fegan failed to pay him 70c for a call.
The trial continues.