MELBOURNE (REUTERS) - On paper, Roger Federer should have little to fear from Andy Murray in Friday's Australian Open semi-final, holding a 3-0 record over the Scot in grand slams.

But respected coach Darren Cahill says Murray has been galvanised by Olympic gold and has his best chance yet of grand slam success over the Swiss.

Australian Cahill, who helped Lleyton Hewitt and Andre Agassi reach world No. 1, said Murray had shown massive improvement over the past 12 months.

His relationship with coach Ivan Lendl has borne fruit on both the playing and mental side of the game, and the Scot's win over Federer in the London Olympics final went some way to healing the wounds of Wimbledon suffered a month earlier.

"I think Andy has made great progress over the last 12 months, more of an understanding over what he needs to get done and how to get it done, in the big moments," said Cahill.

"Again, playing Roger is a completely different thing and you can't put your finger on what is eventually going to help him get over that hurdle in a slam. I think he's 0-3 against him in majors.

"It's a factor, I'm not sure how big a factor that is," Cahill added in an interview on thetennisspace.com.

While Murray, who won his maiden slam at the US Open last year, holds an overall 10-9 record over Federer, the 17-times grand slam champion typically saves something special for the game's biggest stage.

"I think the Olympics went some way to erasing that but in the end Roger is incredibly difficult to beat in majors and until you do it there's always going to be that small element of doubt in your mind," he added.

"But it looks like Andy's prepared as well as he can, he's playing exceptionally well, so if he's going to do it, it's probably as good a time as any."

While some saw Federer's decision to skip traditional warm-up events before the Australian Open as a sign the 31-year-old is starting to feel the effects of age on his fitness, the Swiss has rarely looked out of breath throughout the tournament.

Taken beyond three sets just once, by Jo-Wilfried Tsonga in Wednesday's quarter-final, Federer was likely to show more aggression against the Scot on Friday, said Cahill.

"I think he will try to change the way he played at the Olympics, he added.

"How he feels physically will maybe determine how aggressively he comes out at the start but I think you'll see someone that's going to take the game to Andy."

Murray had lost four grand slam finals, and six semi-finals, before his win over Novak Djokovic in last year's United States (US) Open, and Cahill said the time spent analysing tactics and his game with Lendl was paying dividends.

"It's the stuff that goes on behind closed doors, the talking about big matches about what you were thinking in those periods, talking about strategy and talking about planning for the future," Cahill said of Lendl's influence.

"And no one's privy to that. I think that's where Andy's making the biggest steps forward.

"And I see a certain amount of belief. It's not that it wasn't there before but there was always that little bit of doubt in the big moment. Once he got to the semi-finals you could see that he was just a little intimidated at that particular stage.

"He doesn't seem like that anymore."