The Liverpool Football Club captain is accused of attacking businessman Marcus McGee, 34, after a row over music in a bar.
The 29-year-old was with friends at the Lounge Inn in Southport, Merseyside, in the early hours of December 29 when his party clashed with McGee, a member of another group.
The prosecution says Gerrard, from Formby, Merseyside, became furious that his request was refused and "lost it", punching Mr McGee "with the style and speed of a professional boxer".
At Liverpool Crown Court, Gerrard denies affray and says he was acting in self-defence, having mistakenly believed Mr McGee was about to attack him.
Five of his friends have already admitted affray.
They are Ian Gerrard Smith, 19, of Hilary Avenue; John Doran, 29, of Woodlands Road; and Paul McGrattan, 31, of Linden Drive, all Huyton; and Accrington Stanley footballers Robert Grant, 19, of Enstone Avenue, Litherland; and Ian Dunbavin, 28, of Guildford Road, Southport.
Another friend, John McGrattan, 34, of Rimmer Avenue, Huyton, admitted threatening behaviour.
The jury was sent out shortly after 11.25am today.
Judge Henry Globe QC, the Recorder of Liverpool, described the events at the Lounge Inn as an "explosion of violence".
He said it had been a short trial in relation to an even shorter incident but added: "The shortness of the trial does not mean the case is unimportant.
"It is of considerable importance to all parties - Marcus McGee, Steven Gerrard and everyone who became involved in the explosion of violence at the Lounge Inn bar in Southport last December."
Judge Globe added: "Put aside any football loyalty for impartiality and try the case on the evidence."