Roger Federer explains why top seeds have failed at the Australian Open

The Plexicushion surface that has been used at the Open this year has increased its speed dramatically, and the 35-year-old said that it resembled a surface from a decade ago when all the courts used to be fast. Six of the eight semi-finalists are above the age of 30 which suggest that Federer might have a good point.

"I think with faster conditions, the older generation, I'm saying like anything before 2005, they are used to faster courts. From that moment on, it was a switch. Maybe it was shortly before that. I'm not sure. But we had to grow up in faster conditions," Federer said during the post-match press conference, reported The Sydney Morning Herald.

"Everything changed as time went by. I think if you look at also Venus(Williams), she loves the fast courts. She always has. I think it just is natural for her to play well on this surface because maybe there's less thinking going on, you just play with instinct. That's maybe what older guys can do very well because they don't get frustrated in faster conditions."

Mischa Zverev, who was ousted by Federer in the quarterfinals, had knocked out World No. 1 Andy Murray in the fourth round by playing a game of a bygone age - the serve-and-volley. Federer also said that it has become very difficult for the players to ply a serve-volley style after the slowing down of the surfaces and advances in racquet technology.

Read : Australian Open | Five best matches in Week 1

"The game has changed. Tournament directors chose to make it slower. Tennis balls have become slower too. That's OK. I had to adapt my game and play a different kind of style.

"The conditions [this year] have allowed me to play forward and I thought Mischa (Zverev) did a terrific job this tournament and I hope it's going to inspire more players to do that in the future," Federer added.