* Murray wins in five sets
* To meet Djokovic in final
MELBOURNE, Jan 25 (Reuters) - Andy Murray won a knock-down-drag-out thriller of a scrap with Roger Federer on Friday to set up an Australian Open final against Novak Djokovic and finally beat the Swiss for the first time at a grand slam.
Charged with confidence after claiming his first grand slam title at last year's U.S. Open and beating Federer in the Olympic final, Murray met the Swiss as a peer and prevailed 6-4 6-7 6-3 6-7 6-2 after four hours of top quality tennis.
The 25-year-old Briton blasted 21 aces and won the winner count 62-43 but it was only in the fifth set that he was able to pull away from the 17-times grand slam champion to reach his third Melbourne Park final.
Federer was never going to give up easily and twice came from a set down to level a sometimes fractious contest before the effort of playing back-to-back five set matches took its toll on his 31-year-old legs.
"It was a tough match (but) I thought I did a good job tonight," said Murray.
"I've obviously lost some tough matches against him in slams. So to win one, especially the way that it went was obviously nice."
Murray had never beaten Federer in their three previous meetings at grand slams and now has the chance to become the first man in the open era to back up his maiden major title at the first attempt.
To do that, though, he will have to beat double defending champion Djokovic, who crushed the Scot in the 2011 final and played one of the best matches of his career on Thursday to hammer David Ferrer and reach his third successive final.
"I don't want to be wasting any energy, because I'll need all of it if I want to win against Novak on Sunday," said Murray.
With two of the "Big Four" of men's tennis facing off for the first time in the tournament, there was a real buzz as the pair took to the court on Rod Laver Arena.
The capacity crowd would not be disappointed and watched mesmerised as they did battle through lengthy rally after lengthy rally, only the squeak of their shoes on the bright blue surface and the occasional gasp breaking the silence.
Once all sinew, Murray has muscled up considerably and his increased power was evident in his service and some huge forehands that forced the four-times Australian Open champion onto the backfoot.
Power on its own has never been enough to beat Federer, however, and it was the acute angle of the third seed's crosscourt winner that gave him a break to go 2-1 up in the first set.
Federer put huge pressure on Murray's next couple of service games but the Briton showed his increasing maturity to hold where he might once have crumbled and go a set up.
There were no break points in a tight second set but Federer got his nose ahead in the tiebreak, setting up set point with a beautiful backhand pass and yelling "Allez!" as he converted it.
It was the first set Murray had lost all tournament and he looked intent on making it the last, breaking for 4-2 in the third when Federer went wide with a backhand and closing out comfortably with his 16th ace.
Federer was still not done, however, and two hours and 42 minutes into the match he finally got his first break when Murray went wide with a forehand in the 71-minute fourth set.
Murray's brilliant returning helped him break straight back, however, and he was in front with another break four games later but just could not serve out for the victory.
"When I was serving for the match at 6-5 in the fourth, he came up with some unbelievable shots," said Murray, who lost the ensuing tiebreak 7-2.
Murray raced to a 3-0 lead in the decider, however, and was soon raising his arms in triumph after reaching his sixth grand slam final.
"It was tough tennis. I enjoy that," said Federer.
"I think Andy was a bit better than I was tonight. He beat me fair and square tonight. No regrets from me.
"He's always played me pretty well over the years. With the win at the Olympics and the U.S. Open ... it seems like he has more peace when he plays out there."
Earlier, Italian duo Sara Errani and Roberta Vinci beat local hopes Ashleigh Barty and Casey Dellacqua 6-2 3-6 6-2 in the women's doubles final to claim the first title of the tournament.
Four titles are up for grabs on Saturday, the highlight being the women's singles final where China's Li Na and defending champion Victoria Azarenka will fight it out.
Murray will have the day off before meeting Djokovic on Sunday, when he will be looking to break Britain's 78-year drought without an Australian Open men's champion. (Editing by Toby Davis)