Australian Open 2017: The return of Roger Federer and Rafa NadalUpdated 1735 GMT (0135 HKT) January 24, 2017 Chat with us in Facebook Messenger. Find out what's happening in the world as it unfolds. Photos: Tennis greats roll back the years at Melbourne ParkPrior to the Australian Open, Roger Federer had dropped out of the world's top 10 rankings because of a six-month absence from the Tour with a knee injury.Hide Caption 1 of 7 Photos: Tennis greats roll back the years at Melbourne ParkBut the 17-time grand slam champion has returned to form in Melbourne Park, going further in the tournament than top seed Andy Murray and defending champion Novak Djokovic. Hide Caption 2 of 7 Photos: Tennis greats roll back the years at Melbourne ParkFederer's opponent in the quarterfinals was the unseeded Mischa Zverev, the world No. 50 who had surprisingly knocked out favorite Murray in the fourth round. Hide Caption 3 of 7 Photos: Tennis greats roll back the years at Melbourne ParkThe 35-year-old Federer surprised himself -- but perhaps not his devoted fans -- as he destroyed the German in straight sets in just 92 minutes to reach his 13th Australian Open semifinal. Hide Caption 4 of 7 Photos: Tennis greats roll back the years at Melbourne ParkThe Swiss' joy at progressing was evident as he became the oldest player to reach a grand slam semi-final since a 39-year-old Jimmy Connors did so at the US Open in 1991. Hide Caption 5 of 7 Photos: Tennis greats roll back the years at Melbourne ParkFederer, ranked world No. 17, could play old adversary Rafael Nadal in the final Sunday, a player he has only beaten in 11 of their 34 previous meetings. Hide Caption 6 of 7 Photos: Tennis greats roll back the years at Melbourne ParkBut first Federer must overcome compatriot and three-time grand slam champion Stan Wawrinka in the semifinals for a shot at winning a fifth Australian Open title. Hide Caption 7 of 7Roger Federer and Rafa Nadal had their injury problems in 2016. But both look back to their best at the Australian Open.More from Sport - TennisSerena Williams ties the knot at 'Beauty and the Beast' themed weddingRafael Nadal wins defamation case over doping claimsCaroline Wozniacki beats Venus Williams for first time to win WTA FinalsUnited States beat Belarus to win first Fed Cup title since 2000U.S. tennis star Jack Sock takes CNN's 'Sock Challenge'!!