Nelson was one of several youngsters to be given a chance by manager Arsene Wenger and despite playing out of position at wing-back, the 17-year-old left a huge impression on Keown.
Speaking on 'BT Sport' after the game, the former England international said that Nelson reminded him in many ways of Neymar and lavished praise on the youngster.
'Congratulations to those young Arsenal players,' said Keown.
'All those nervous parents watching their kids playing miles away from home and I thought all of them were magnificent in the way they played, particularly Nelson.
'He showed the sort of touches that you often see or associate with a Neymar or a real top player, he was breezing past players and Wenger will know the quality that he has.
'17 years of age, it’s quite phenomenal the ability this boy has. There’s certainly a big future there, he really does look a wonderful talent.'
Nelson has made four appearances for Arsenal so far this season but if Keown is right, they will merely be the first of many in an Arsenal shirt for the player.