Peter Grant praised Jon Dagur Thorsteinsson's mentality to want to continue playing in their 3-2 defeat to Charlton despite not being well at half time.
The 18-year-old scored and assisted in the U21s 3-2 defeat to Charlton at the Valley in the Checkatrade Trophy and got the sparse crowd excited throughout the game, setting up a number of dangerous attacks from the left wing.
In a world where modern day young footballers are seen to be bubble wrapped by some members of the public, Grant believes Thorsteinsson's mentality to want to continue playing is a credit to the youngster who possess "top quality".
He said: "He's been excellent - he's a terrific young player and he was struggling, at half time he was being sick in the room and I said to him does he want to come off but for a young man to stay on, in the modern day they all get criticism for wanting to come off and being soft touches but to be fair to that kid he wanted to stay on and finish the game.
"Even late in the game before he scored the two goals I was ready to take him off actually, but then I thought with the equaliser that he's good at penalties so that's why I kept him on and then all of a sudden they get the winner.
"His performances have been excellent and he's definitely got top quality, he sees pictures others don't see and he's not the quickest player but he has a fantastic quick brain."