The Bianconeri failed were eliminated at the group stage of Europe's premier cup competition last year but announced themselves are serious contenders for the 2014-15 crown by routing Borussia Dortmund 5-1 on aggregate in the last 16.
There has never been any love lost between Inter and Juve, two of Italy's traditional superpowers, but Zanetti has no problem admitting that the runaway Serie A leaders are capable of winning the Champions League.
However, the former Argentina international says Massimiliano Allegri's men must not make the mistake of looking past quarter-final opponents Monaco, who shocked Arsenal in the previous round.
"Juve can win the Champions League," the Nerazzurri icon told Mediaset. "But they must beware of underestimating Monaco.
"All of the teams who have gotten to this point are strong and they can all fight to reach the final."
Inter, of course, were the last Italian team to win the European Cup, with Jose Mourinho leading the San Siro side to glory in 2010.
However, they have been in a steady decline ever since and new owner Erick Thohir is now trying to restore the club to their former glory.
The fans are growing increasingly frustration with the Indonesian's leadership but Zanetti says his boss needs more time to turn things around.
"Thohir is trying to build an important club, but we must remember that it's his first year at Inter," he pointed out.
"He needs time and in Italy that's not easy. But we all want to contribute to the creation of a competitive squad and the president most of all wants to build a great Inter."