He managed to stagger a short distance away from the scene of the alleged attack, but died at the scene.
Bhoniefas Rexson, 18, was charged on Friday with murder and possessing a knife, and appeared at the Old Bailey for the first time this morning.
“The allegations are murder and possession of a bladed article in a public place, in respect of the fatal stabbing of Gedeon Ngwendema in Brent Cross shopping centre on May 4,” said prosecutor Sarah Przybylska.
“The prosecution’s case is there was a single stab wound to the chest which penetrated the heart.”
She said Mr Ngwendema “made it a little way away, holding his chest, and then collapsed”.
Rexson, from Kingsbury in northwest London, was arrested on the same day as the stabbing.
It is said he inflicted the fatal stab wound in the incident, which happened about 6.40pm.
Judge Angela Rafferty QC remanded him in custody until a plea hearing on August 2.
No date has been set for a trial, and Rexson has not yet entered any pleas.
Police have said a 20-year-old man was arrested on suspicion of murder at his home in Harrow last Wednesday, and a 22-year-old man was detained on Tuesday on suspicion of murder and affray. Both have been released on bail.