The 84-year-old, who won the European Cup six times with Real in the 1950s and '60s before becoming an ambassador for the club, is looking forward to the Kiev showpiece on May 26.
Asked if he was confident that Real would prevail against Liverpool, Gento is quoted by the Daily Mail as saying: "That goes without saying, it will be a piece of cake.
"Everyone gets excited by these kind of games. Everyone wants to be there to support the team and cheer them on to win another European Cup and continue this great run we're in and which we have always enjoyed.
"Madrid cannot let this chance slip - finals are to be won, not played and Real Madrid know what is at stake."
Real have won European football's elite competition 12 times in their history.