The pair, both renowned attacking players, were regular opponents in Serie A and were competitors for a place in the Italy team in the 1990s.
And Manchester City boss Mancini says he is a big fan of Zola, who was West Ham boss for two years before being sacked in 2010.
"I respected him as a player when he played and now as a manager. I think he did a good job when he was at West Ham and now with Watford," he said.
"He was a fantastic player, his quality was of top level. He did very well in Italy and very well in England with Chelsea.
"As a manager you need time but he still did very well with West Ham and I think he has a good chance to bring Watford into the first division because he knows football very well."
Zola's Hornets can expect to face a strong City side as Mancini insists he has few options within his squad for the game.
"The FA Cup is totally different from the Premier League. Probably for Watford it is the most important game in the year and we won't change a lot of players - we don't have the players," he said.