Roger Federer and Rafael Nadal are pushing the boundaries and raising the bar like never before.
World sport’s most compelling individual rivalry reaches a new level on Friday night when tennis’s two grand slam gluttons fight for an Australian Open final berth – and a whole lot more.
With Nadal rapidly closing in on Federer’s all-time record 17 grand slam singles crowns, the Swiss master’s long-held standing as the GOAT – greatest of all time – is no longer secure.
Where once the critics dismissed Nadal’s winning record over Federer as an anomaly owing to the claycourt colossus’s red-dirt ruling of the roost, suddenly the Spaniard’s 22-10 head-to-head advantage can no longer be ignored.
The recurring question now is how can any man be considered the GOAT when he loses to his greatest rival over and over again?
Federer could argue that, at almost 33, the fact he’s even still making grand slam semi-finals and competing with Nadal – and beating Andy Murray and the like – when his younger challengers are at the peak of their powers is reason enough.
But, as they keep saying in this tough new world, “it is what it is” and losing more than twice as many matches than he’s won against Nadal fuels the debate.
Which raises the stakes even higher for the 33rd running of Federer versus Nadal on Friday night at Melbourne Park.
Victory for the Swiss and he will be favoured to win Sunday’s final and lift his grand slam tally to 18, a comfortable buffer of five over the ever-chasing Nadal.
But defeat for the Artful Roger and Nadal will be fancied to take his major haul to 14, equal second with Pete Sampras, just three shy of Federer and, at 27, with the promise of more good years to come.
Unless the Spaniard goes all weak at the knees, again.
Tennis analyst Todd Woodbridge acknowledges the coming three days can help define Federer’s grand career.
“I still think that he needs to take out Rafa a couple of times in these to really go to another level again,” Woodbridge told AAP.
“Because Rafa might catch him and then we’ll have this debate for a while yet.
“So quite a lot rests on these next few days.”
With it all on the line, Federer and Nadal are pushing the limits on court and off.
Once a coachless genius who confessed to taking the court without even a plan, Federer turned to childhood idol Stefan Edberg to re-energise him after enduring his worst season in more than a decade in 2013.
He gambled with a new racquet and is winning the big matches again after upgrading to a larger, more powerful frame.
“I do believe I have easier power with the racquet on the serve,” he said.
With 77 holds from 79 service games this Open campaign, there can be no doubt.
“It might help me on the return as well,” Federer said. “I hope it is the case.”
With seven service breaks in virtuoso displays against Murray and Jo-Wilfried Tsonga in his past two matches, this assertion is certainly true too.
Most importantly, though, nagging concerns that his ageing body – specifically a creaky old back – will fail him like it did last year are gone after Federer spent the off-season rehabilitating and training like never before.
“I don’t have any doubts anymore,” he said.
And in his single-minded pursuit of an 18th career slam – a magical number to match Jack Nicklaus’s 18 golf majors and swimming superstar Michael Phelps’ 18 Olympic gold medals – there can be no quarter given.
Federer admitted he was unsure if he’d won a key point after a double-bounce in his stirring quarter-final victory over Murray on Wednesday night.
An agitated Murray questioned whether Federer had reached the ball before it bounced twice.
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 it hit the ground first”.
“But it’s impossible for (umpire) Pascal Maria to know and for Roger to know,” Courier said.
Federer, a nine-times winner of the ATP’s Stefan Edberg sportsmanship award, said he “honestly” didn’t know if it was a double-hop or not.
“I thought I probably got it, especially the way it bounced on the other side,” he said.
“We’ll have to check the replay time and time again … I hope it was played the right way. If it wasn’t, I’m sorry.”
Debate will continue to rage, but Federer has moved on. To him, that’s what matters most.
Nadal, too, has taken extreme measures to revive his grand slam career after losing in the second round of Wimbledon in 2012 and subsequently missing seven months with chronic knee soreness.
Radical and revolutionary treatments including Plasma Rich Platelet therapy – or blood spinning – helped the Spanish powerhouse capture 11 titles from 14 finals in 15 events – including his 12th and 13th majors in Paris and New York – in a spectacular return.
But there have been rule breaches as well, with Nadal warned for receiving illegal courtside coaching and thumbing his nose at the 20-second interval entitlement between rallies during his march through the Open draw.
He questioned chair umpire Evanthia Asderaki for having the audacity to hit the world No.1 with a time violation in his tough fourth-round win over Kei Nishikori.
But rules are rules and whoever rules on Friday night between Federer and Nadal will stake a claim not only for another Australian Open crown, but for the right to be known as the GOAT.