Roger Federer and Rafael Nadal will be looking to serve up another occasion to relish in the Australian Open semi-finals.
It's the 27th meeting between these two great protagonists. Nadal as we know, leads the head-to-head by a huge margin of 17-9 but this is skewed greatly by his dominance of Federer on clay. However Federer has still only beaten the Spaniard once on outdoor hard courts and that was way back in 2005.
Nadal won comfortably when they met in Miami last year and of course won the titanic 2009 Australian Open final between the pair which went five sets and left Federer in tears.
Victory over Nadal on Thursday would mean a lot to Federer and would provide him with a huge psychological boost. He's been experimenting with a number of new things in this tournament - using the forehand drop shot, serve-volleying a little more and looking to run round his backhand and attack the second serve. However this will be the acid test for those tactics.
Nadal experienced his first real test of the tournament on Tuesday when Tomas Berdych pushed him hard for two sets before eventually going down 6-7(5), 7-6(6), 6-4, 6-3 in just under four hours. It proved to everyone that Nadal's body is robust enough for him to go the distance if necessary in this tournament and he'll undoubtedly be as fresh as a daisy for the match with Federer.
This is a tough one to call but with Nadal being the great competitor he is, it's hard to bet against him pulling off another memorable five set win.
