Erik ten Hag says Alejandro Garnacho was "not good enough" in his previous starts this season after the Manchester United teenager scored in the Carabao Cup victory against Crystal Palace.
Having secured a much-needed Premier League victory at Burnley on Saturday evening, the Red Devils ran out comfortable 3-0 victors against Roy Hodgson's south Londoners on Tuesday night.
Casemiro scored and then crossed for Anthony Martial's goal on a night started by Garnacho impressively putting the Carabao Cup holders ahead from Diogo Dalot's cutback.
The 19-year-old began United's first two matches of the season, but this was the first time he was named in the starting line-up since the defeat to Tottenham five weeks ago.
"You have seen at the start of the season we played him and then his contribution was not good enough," manager Ten Hag said of the Argentina international.
"But he also had some good actions. You see always he is a threat in the game even when he is not playing that well.
"He has to learn when he does his job in defending he will always have his moment and he will always be decisive because he has great qualities.
"As well, it's not only off the ball. But I want to see like today, he is entering the box in the right spot to finish.
"But I think it is quite normal for a player of his age that there is space for a lot of improvement.
"Everyone likes him, the fans like him, the team likes him, I like him but we also have to demand from him and push him because he can act on a very high level but he has to show it every day."
United made seven alterations, as did Palace, ahead of Saturday's Premier League reunion at Old Trafford.
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