Zola worked with the 22-year-old when in charge of Italy's under-21 team and admits he likes the striker who has had a tempestuous time at Manchester City - culminating in this week's training ground bust-up with manager Roberto Mancini.
"I have an affection for him. I have worked with him for the under-21s and I do care about him and I do hope his potential is fulfilled," Zola said.
"Even when he came on today you can see the potential in the man, and it's how to master that potential. I do hope he gets to that position as he will be a fantastic player. I am talking about what he can do to improve his situation but it's not down to me to say how."
Carlos Tevez took the plaudits for City however with a dashing performance rounded off by a stunning free-kick. There were also goals for Gareth Barry and on his debut for Portuguese midfielder Marcos Lopes, who only turned 17 last week.
Watford's best chance came with score at 1-0 when Fernando Forestieri was through one-on-one but City's keeper Costel Pantilimon, in for the rested Joe Hart, pulled off an excellent diving save.
Zola added: "Maybe it would have been different if that had gone in. I admit they deserved to win but the scoreline was a bit unfair."
Marcos Lopes is reputedly nicknamed 'Rony' after the Brazilian striker Ronaldinho - but City assistant manager David Platt brushed off any comparisons.
Platt said: "I hope not. His nickname is Marcos and he has played five minutes in an FA Cup tie and scored a goal. He should be proud of that and equally he should be ready to train tomorrow and he will be, with the under-21 team to play in their game on Monday.
"He's a good lad, he's got a very good temperament as well and he won't let that go to his head."
Source: PA
Source: PA