Roger Federer has been written off before, but as a disastrous 2013 draws to a close it is increasingly difficult to see a way back for the Swiss legend.
Federer's status as one of the game's true greats is not up for debate. Critics point out that he has a losing record against Rafael Nadal and Andy Murray, and only just leads Novak Djokovic in the head-to-head stakes.
But 17 grand slam titles do not lie. For a time Federer was head and shoulders above the rest, until Nadal emerged to challenge him. Djokovic and Murray then joined the party, when they were in their mid-20s and Federer was turning 30.
Nadal looks likely to surpass Federer's record haul of majors someday, but one thing he seems destined never to match is his great rival's consistency throughout the years.
Perhaps more impressive than any of the titles he has won is Federer's run of 23 consecutive grand slam semi-final appearances from Wimbledon 2004 to the 2010 Australian Open. At one point during that stretch he reached 18 finals out of 19, including 10 straight.
It is the loss of that interminable brilliance that has led so many to draw the conclusion that Federer's days at the top are over.
His form this year has been worse than at any point since he won his maiden grand slam title in 2003. Federer's last two grand slams ended with second- and fourth-round exits, stages of elimination which would have been unthinkable over the last decade.
On top of that, Federer has reached the final of only one of this year's Masters Series events so far, and he did so in Rome without beating a seeded opponent and was then dispatched in straight sets by Nadal.
Once so prolific, Federer has won just one event in 2013 - the Gerry Weber Open on the grass in Halle, where he edged out Mikhail Youzhny in a three-set final.
He could feasibly end the year on the fringes of the world's top 10 and the warning signs, which at the moment are flashing in neon red, seem to finally be registering.
In a bid to turn things around, Federer first experimented with a new racquet before parting ways with his coach Paul Annacone. It is clear that 2014 has not been scheduled as the last stop on a leisurely retirement tour.
"My mindset now is next year is going to be a great year again where I'm not going to have that many points to defend, especially at some very key moments where I consider myself a favourite," he said recently.
Federer will turn 33 in 2014. Even if he wins the Australian Open at the start of the year, he would be the oldest grand slam champion since Andre Agassi in 2003. From the French Open on, he would become the oldest winner since Ken Rosewall in 1972.
For whatever reason, Federer is clearly not willing to stop chasing one more moment of glory, but his age and historically bad form suggest he may come up empty-handed.
However, we should not use history and statistical trends as our only guides. When 30-year-old Pete Sampras was beaten in the second round of Wimbledon by George Bastl - his sixth early-round exit in seven grand slams - many feared his record-breaking career would end in embarrassment.
Instead it finished in fairytale fashion, with a win at the US Open just two months later.
"I'm not going to give into the critics - I'll stop on my own terms," Sampras said after the Bastl defeat. It would be no surprise if this is Federer's current mindset.
That Federer no longer seems able to control his own destiny clearly rankles with a player who once won grand slams more or less when he pleased.
If a renaissance is to come next year a strong performance at the upcoming ATP World Tour Finals - traditionally one of his strongest events - would be an obvious precursor. But the fact he has not yet even qualified for the London showpiece yet shows how far he has fallen.