Jermaine Joseph, 23, from Tottenham grinned as he was cleared of the murder and manslaughter of Seydou Diarrassouba at the Old Bailey this morning.
He was on trial for the Footlocker store stabbing on Boxing Day last year on Oxford Street which shocked the nation.
The post-mortem revealed 18-year-old Seydou died of a single stab wound to the heart.
The four week trial established that Seydou had been stabbed with a 10 cm (4inch) knife which broke due to the force of the blow.
However, Jermaine Joseph successfully claimed that Diarrassouba was the aggressor and Seydou threatened to attack him with a blade.
The clash lasted seconds and both men are believed to have been members of rival gangs.
Cleared on all counts, Jermaine Joseph is a free man.