Australia's squad includes two 37-year-olds, opener Chris Rogers and wicketkeeper Brad Haddin, along with fast bowler Ryan Harris and batsman Adam Voges who are both 35.
“Jason's entitled to his opinion,” Clarke told reporters on Sunday. “There's a long list of people who've criticised this team.
“We might just add “Dizzy” (Gillespie) to that list of people we continue to prove wrong.”
Gillespie, now coach of English county Yorkshire, has overseen the development of young England batsmen Joe Root, Gary Ballance and Adam Lyth who are all likely to play in the first test against the Australians in Cardiff starting on July 8.
“The senior players deserve a lot of credit for mentoring the younger players and helping them through the tough times and we're seeing a lot of benefit from that,” Clarke said.
“The experience of the senior players is crucial and, hopefully, we can find that perfect mix and we're able to have success.”
The 34-year-old Clarke has been plagued by back and hamstring injuries in recent years while all-rounder Shane Watson is also 34.
Australia do have younger players, including 26-year-old Steve Smith, who is the world's top-ranked test batsman following a prolific run of form, and dynamic 28-year-old opener David Warner.
“A lot of our young players have come a long way over the last few years,” Clarke said.
England have undergone significant changes in personnel since being crushed 5-0 in the last Ashes series in Australia in 2013-14.
Stalwarts including Kevin Pietersen, Graeme Swann, Jonathan Trott and Matt Prior are out of the international reckoning, leaving Alastair Cook as captain of a mainly youthful side.
Only Cook, James Anderson, Stuart Broad, Ian Bell and Root have enjoyed Ashes success, with young players like Ballance, Lyth, Jos Buttler, Ben Stokes, Mark Wood and Moeen Ali poised to experience cricket's fiercest rivalry for the first time. – Reuters
Original source: Aussies will prove critics wrong