"He (Manassero) is so young and if he does what he has to do he can achieve whatever he wants to achieve," fellow Italian Rocca told Reuters in a telephone interview.
"I was very impressed with him in Switzerland (this month). He knew he had to finish in the top five to secure his European Tour card for next year and he did it.
"That was fantastic," added Rocca, who played in the Ryder Cup in 1993, 1995 and 1997 and was runner-up to American John Daly at the British Open 15 years ago.
Manassero came close to recording his maiden victory in Switzerland, finishing third.
He was only 16 when he burst on the scene by finishing tied for 13th at the 2009 British Open and he seems to be breaking records at every turn.
This April Manassero became the youngest ever competitor at the US Masters.
He went on to be the youngest player to make the cut at the season's opening major before ending up in a share of 36th place at Augusta, the best performance by a European amateur for 73 years.
Manassero turned professional in May, making him the second youngest player to join the European Tour after Seve Ballesteros.
Rocca, who now competes on the senior circuit, won five times on the European Tour and is recognized as the finest male golfer Italy has produced.
The 53-year-old remembers meeting Manassero when the youngster was four years old.
"I met him again three or four months ago and I couldn't believe it," said Rocca. "He showed me a picture of when he was four at the Italian Open in 1997.
"He asked to play a match with me and Seve at chipping, that was unbelievable.
"We had a game and he beat me, he chipped so nice at four years old. It's impossible to beat Seve at chipping but this little boy impressed me so much," added Rocca.
"I told him three or four months ago that he spoke more to me when he was four than he does now."
Manassero may have been short of words in his recent meeting with Rocca but he is sure to be watching closely and learning plenty when Europe take on the US holders at next month's Ryder Cup at Celtic Manor in Wales.
Rocca, the only Italian to have previously played in the biennial team event, will be cheering from the sidelines as compatriots Francesco and Edoardo Molinari make their Ryder Cup debuts from Oct. 1-3.
