Manchester City coach David Platt was delighted for 17 year-old Mario Lopes after his debut in their FA Cup win over Watford.

Lopes was introduced with five minutes to play and scored with one of his first touches to put City in the pot for Sunday's FA Cup fourth round draw with a 3-0 win.

"He's got a big smile on his face at the moment, I can tell you that," Platt revealed in the post-match press conference.

"Marcos has played five minutes at the end of an FA Cup tie and he's scored a goal, he should be proud of what he's done but equally he should be up tomorrow and ready to train hard which he will be because he's got a good temperament and he won't let this go to his head."

The 17-year old forward has been in prolific form for Attilio Lombardo's EDS side in the first half of the 2012/13 season, so Platt wasn't surprised at his clinical finish in the dying embers of this third round tie.

"He came away with us on pre-season and did very, very well, he's a very technical footballer, you can see that he wants to go and hurt the opposition," Platt declared.

"He's got great qualities - for the under-21s he's been scoring goals like that this season."