Roger Federer has set up a 33rd instalment of his great rivalry with Rafael Nadal with a drama-charged Australian Open quarter-final triumph over Andy Murray.
The revitalised former world No.1 delivered another masterclass to put Murray to the sword 6-3 6-4 6-7 (6-8) 6-3 in a compelling encounter loaded with sublime shot-making and lung-busting rallies but laced with controversy as well.
An agitated Murray questioned whether Federer had won a key point deep in the third set on a double bounce before breaking the Scot to claim a 5-4 advantage and an opportunity to serve out the match in straight sets.
Television replays proved inconclusive, with former world No.1s Jim Courier and Lleyton Hewitt initially both unsure.
But after taking several more looks, Courier said it was "60-40 that that it hit the ground first" - and 70 per cent of TV viewers on a Channel Seven poll agreed.
"But it's impossible for (umpire) Pascal Maria to know and for Roger to know," Courier said.
After being broken two points later, Murray complained to Maria at the changeover but the incident seemed to fire the Wimbledon champion up - and rattle Federer.
Having not faced one solitary break point, Federer was unable to serve out the match when play continued after Murray's spat.
Federer then blew two match points in the third-set tiebreaker and was unable to convert any of six break-point chances in a marathon second game of the fourth set as tension mounted.
Rod Laver was in the house - but only just - for all the enthralling action as Federer regrouped to finally see off Murray after three hours and 19 minutes of mostly breathtaking tennis from the Swiss maestro at Rod Laver Arena.
With traffic gridlocked in Melbourne, Laver was forced to ditch his car and take a tram to make it on time to the venue named in his honour.
But any inconvenience was worth it, with the 75-year-old tennis legend treated to a veritable feast from the 17-times grand slam champion early on.
With new coach Stefan Edberg nodding approvingly from Federer's courtside box, the brilliant Swiss clubbed winner after winner and landed 80 per cent of first serves to have Murray staring down the barrel of a three-set lesson.
Tellingly, Federer also made 49 successful forays to the net in another clear statement of intent, two nights after showcasing his bold new attacking mindset in a straight-sets domination of Jo-Wilfried Tsonga.
Until his late stumble, the four-time Open champion was again nigh impregnable on serve and has won 77 of his 79 service games this campaign.
When Murray served, he struggled to hang on - especially as fatigue beset the world No.4 as the night wore on.
An underdone Murray only played two competitive matches in four months before the Open after undergoing back surgery after the US Open.
Federer broke him once in each set, the last decisive time in the eighth game of the fourth set as the Scot began to seize to finally book his big date with Nadal on Friday night.
The world No.1 earlier on Wednesday needed three hours and 37 minutes to defeat Bulgarian 22nd seed Grigor Dimitrov 3-6 7-6 (7-3) 7-6 (9-7) 6-2 in the first quarter-final.
It will be the first grand slam meeting between the two tennis titans since Federer and Nadal also clashed in the semi-finals at Melbourne Park in 2012.
Nadal won that encounter in four tight sets before falling to Novak Djokovic in the longest grand slam final in history, a five-hour, 53-minute classic.