It was a blast from the past when Roger Federer and Rafael Nadal took centre stage at the Australian Open last year. The flashback slam got the finish it deserved when Federer outlasted his good friend Nadal in a colossal five-set battle on Rod Laver Arena.
Fast forward 12 months and it is hard to envisage the two tennis greats going head-to-head again in a showdown for the ages at Melbourne Park on January 28 – and it is all because of the 31-year-old Spaniard and world number one.
Federer and Nadal's preparations for the Australian Open could not be more contrasting as the latter deals with an ongoing knee problem which continues to threaten his bid for a second Melbourne title and first since 2009, when he left the Swiss maestro weeping like a schoolboy on RLA.
A knee injury which has prevented Nadal from playing competitively since losing to David Goffin at the ATP Finals in November has restricted the 16-time major champion to just a pair of exhibition contests in Melbourne – a far cry from his run to the quarter-finals at the Brisbane International last year.
Nadal – who withdrew from the Mubadala World Tennis Championship and the Brisbane International – lost to Richard Gasquet at the Kooyong Classic on Tuesday before going down to Tomas Berdych in the Tie Break Tens tournament a day later.
What was more concerning, albeit in an exhibition, was his performance against retired 36-year-old Lleyton Hewitt in the semi-finals of the event – first to 10 points – having survived match points against the Australian.
Nadal now heads into the year's opening slam, where the top seed will kick off his campaign against Victor Estrella Burgos, with more questions than answers.
"Last year's season was a bit long and I had to start a little bit later than I would've liked. For me it was not ideal to not be in Brisbane, I would have loved to be there but I had to make a different schedule this year," Nadal said during the week.
"For the first time I have to play here at the Australian [Open] for the first tournament of the year. I'm excited about it and I've got a few days to practice."
As for Federer, it is business as usual in his pursuit of a remarkable 20th grand slam.
While Nadal and six-time Australian Open champion Novak Djokovic battle to prove their fitness following the withdrawal of five-time runner-up Andy Murray, defending champion Federer is pain-free and enjoying a relaxed build-up.
An unlikely winner at Melbourne Park in 2017 before going on to capture Wimbledon, the evergreen 36-year-old – who enjoyed a renaissance last season having been struck down by injuries in 2016 – is trusting his tried and tested preparation, having featured at the Hopman Cup in Perth just like he did last year.
There is a difference, however, with Federer guiding Switzerland to their third Hopman Cup trophy – 17 years on from claiming the title alongside Martina Hingis.
"Everybody thinks I probably have a good chance to maybe repeat and other guys are maybe a bit hurt," Federer said recently before being drawn against Aljaz Bedene in the opening round. "All these things all play into it but at the end of the day I've been in this position thankfully many times before.
"Defending a title the very first time is the hard part… if you don't win, it's all dramatic but later on in life you take it as it comes, try your best and if it works out, great but if it doesn't, it just doesn't."
The tennis community and sporting world yearns for another instalment in the Federer-Nadal rivalry but while form is temporary and class is permanent, a lack of preparation may rob the Australian public of another unforgettable event.
|Billy Vunipola ruled out with fractured arm|
|Get the chequebook out! - Mayweather talks up potential Khabib clash|
|Amla ruled out of Australia tour|
|Class act Hamilton more complete than ever - Wolff|
|NBA 2018-19: It´s a big season for - Ball, Kawhi, Carmelo, Love & Cousins|
|Bellew: I have no fear of Usyk|
|Birthday boy Ozil is the most creative player in Europe|
|CSA reveals De Villiers and Rabada involved in Mzansi Super League|
|FA condemns England supporters involved in trouble in Seville|
|Gascoigne hits back over Scottish Hall of Fame snub|
|NBA 2018-19: LeBron closing in on Jordan, Curry chasing Miller and Allen|
|Ter Stegen should start ahead of Neuer for Germany – Matthaus|
|England´s Sterling impressed by Sancho´s work ethic|
|Vandoorne seals switch to Formula E|
|Halep to end 2018 as world number one|
|Sri Lanka´s Jayasuriya charged by ICC with breaching anti-corruption code|
|Vermaelen out for six weeks with hamstring injury|
|LeBron and Irving did not fall out, says ex-Cavs trainer|
|Ramsey out of Wales´ clash with Republic of Ireland|
|Bolt angry with drugs test|
|Bad luck is not a coincidence – Kimmich concerned by Germany form|
|Mahomes: Chiefs need to win like Brady and the Patriots|
|Schuster warns Real Madrid not to panic-buy striker in January|
|We´re here to win! - Paine not happy celebrating a draw|
|Injured Thauvin out of Germany clash|
|Southgate hits out at early Premier League start|
|Modric to Inter talk is ´fantasy´, says Guardiola|
|Pats hand first loss to Chiefs after wild shoot-out|
|Cowboys, Ravens dominate as Pats beat Chiefs in NFL classic|
|Brady becomes first QB to 200 regular-season wins in NFL|
|Red Sox level series against Astros|
|Mbappe leaves red-faced Dembele on his backside|
|Red Sox ace Sale admitted to hospital with stomach illness|
|From UFC to NFL? McGregor throws pass for Cowboys|
|Ancelotti praises ´dangerous´ Mbappe|
|Uncapped Papalii named in All Blacks squad|
|Kane would star in LaLiga – Ramos|
|Guardiola unsure about Man City´s Champions League chances|
|Dzeko: Premier League return? You never know|
|Gurley dominates to help Rams beat Broncos|
|Butler expected to play Timberwolves´ opener against Spurs|
|I´m no wizard – Mancini asks for patience with Italy|
|The Messi and Ronaldo era is phenomenal – Guardiola|
|Dolphins defeat Bears in OT with 47-yard field goal|
|Almirola picks up win at Talladega|
|Wigan´s Sarginson wanted Grand Final glory in memory of brother|
|McLeish: Scotland keep shooting themselves in the foot|
|Sarries´ walking wounded a concern for Jones|
|Poland 0 Italy 1: Biraghi seals last-gasp win to keep final-four hopes alive|
|Seahawks top Raiders with blowout win in London|
|In-demand Hogg hints at Glasgow exit|
|Holder calls on Windies batsmen to step up after India whitewash|
|France´s World Cup win hurt me - Koscielny retires from international football|
|Bailey performs U-turn on Jamaica call-up|
|Evans becomes Buccaneers´ all-time leading receiver|
|Overlooked Alba is one of the world´s best, says Ramos|
|Del Potro a major ATP Finals doubt due to fractured patella|
|Gomez to replace suspended Stones for England|
|Luis Enrique applauds ´adaptive´ Southgate|
|Pepperell holds off Bjork for wire-to-wire British Masters glory|
|Steelers´ Shazier returns to Bengals´ stadium for first time since injury|
|Scotland 1 Portugal 3: Santos´ side pile misery on McLeish|
|Falcons prey on Toulon, Vunipola brothers injured in Sarries win|
|N´Golo Kante is fundamental for France – Lucas Hernandez|
|Real Madrid star Bale withdraws from Wales squad|
|50 Cent to meet Khabib for Bellator talks|
|Drink-driving charge does not change who I am – Lloris|
|Pavard backs Varane to beat favourites to Ballon d´Or|
|Gareth gives players more input - Henderson explains Southgate, Klopp contrast|
|Stephens qualifies for WTA Finals as Svitolina sits out Kremlin Cup|