Roger Federer has been a man reborn in Melbourne, and he believes that his new alliance with Stefan Edberg could help him turn the tide, writes Simon Briggs

How fast the tennis world spins. A year ago, we left Melbourne talking about Andy Murray's rivalry with Novak Djokovic as the future of the game. Now both men have gone out in the Australian Open quarter-finals, and the stage is left to their elders and - for this week at least - betters.

Roger Federer 's semi-final against Rafael Nadal on Friday will be the hottest ticket in town. The precedents all favour Nadal, who leads their head-to-head meetings by 22 to 10. But Federer has been a man reborn in Melbourne, and he believes that his new alliance with Stefan Edberg could help him turn the tide.

"When Stefan came to Dubai [in December] and we spoke about the game, we clearly spoke about playing Rafa," Federer said. "He thought he had some good ideas, so I'm looking forward to what he has to say."

Federer was mesmerising against Murray on Wednesday, serving with dead-eyed precision and drifting into the net with the stealth of an assassin. His four-set win was a masterpiece of tactics as well as execution, and suggested that Edberg's input has been as much of a factor in his vastly-improved performances at this tournament as his new, 98-inch Wilson racket.

Nadal, by contrast, has been serving with less than his usual vigour because of a huge blister on the palm of his left hand. In Wednesday's first quarter-final, he dropped the opening set against Grigor Dimitrov - the emerging Bulgarian who plays a similar game to Federer's, only with less consistency.

After the match, Nadal was asked whether he had been bothered by the protective tape he is wearing across his palm.

"With the serve, a little bit," he replied. "I feel that with the tape I can lose the racquet when I serve. That's a terrible feeling for a serve, because then you are not able to accelerate at the right moment. You lose a little bit of the coordination. Yeah, that's a big deal. I served slower. I served bad."

The injury has clearly left Nadal vulnerable, and he might even have found himself booking a flight home had Dimitrov not wasted some fantastic opportunities, particularly an easy forehand that would have put him in front by two sets to one.

Asked about this forehand in his post-match press conference, Dimitrov became so emotional that he could barely speak. "What can I say?" he choked out. "It hurts. You know, it's just a tough shot, a tough choice. I'm sure I could have done something different. But, in a match, everything comes down to a split second."

Though Dimitrov wound up losing by a 3-6, 7-6, 7-6, 6-2 margin, he can look forward to one consolation: he will crack the top 20 for the first time next week.