What do you do when you keep getting beaten by the same bloke? You go looking for counter-measures, right? Well, apparently not if your name is Roger Federer or Rafael Nadal.
Before Christmas, the two grandees of men's tennis both stressed that they would not be using the off-season to search for methods of disconcerting Novak Djokovic.
Are they in denial? Or is it just professional pride that prevents them from changing their practice routines? What seems particularly optimistic is the idea - stated again by Nadal after Djokovic smoked him in Doha a week ago - that the younger man's level will drop at some unstated point in the future.
You have to wonder whether they have been paying attention, for they are dealing with someone who has reached the final in 18 straight tournaments.
Perhaps the Big Two have had it so good for so long that they find it difficult to accept the new reality.
For this is the age of Novak. As ESPN commentator Brad Gilbert put it last week: "He is as complete a tennis player as I've ever seen. Just the way he's playing right now, I think he's going to have an incredibly monster year."
It feels as if the arithmetic of the game has simplified itself. Until relatively recently, Djokovic's inner fires had been prone to boil over in the biggest matches. How else do we explain that bizarre two-year sequence - stretching between the French Opens of 2012 and 2014 - when he lost five out of six grand slam finals? Unfortunately for the rest of the field, Djokovic seems to have exorcised those demons. Since the 2014 Wimbledon -- the point when he reached some kind of mutual understanding with coach Boris Becker - he has shown fewer signs of weakness. Just ask the bookmakers, who make him the odds-on favourite to win the Australian Open, which starts tomorrow. They appreciate the simple fact that you do not win major events without beating Djokovic along the way.
And yet, we must return to the answers given by Federer and Nadal in November, when asked whether they would dedicate their off-seasons to cracking this mission impossible.
"Not really," said Federer. "I know I will have chances with my game."
As for Nadal, he replied, "I never practise thinking about others. What Novak is doing is just amazing ... but it's not easy to stay at that high level."
Why are they so stubborn? One reason may lie in their enduring popularity. Few fans of either man have defected to Djokovic, whose struggle for international resonance has elements in common with Ivan Lendl's. No matter what happens on court, Federer and Nadal continue to soak up the biggest endorsement deals, viewing figures and crowd reactions, which must ease the pain of dropping down the rankings.
They may also feel the numbers are on their side. With 10 grand slams to his name, Djokovic remains at least a year's worth of majors behind Nadal (14) and two years' worth behind Federer (17). If Nadal is right, and a dip in form is inevitable at some point, he may never catch them at all.
Mats Wilander, the Swedish champion who will commentate on the Australian Open for Eurosport, also subscribes to the view that Djokovic is mortal. To his mind, the world No1 has the potential to fade as quickly as Lleyton Hewitt in the mid-2000s.
"I've experienced it as a player and I've seen it with others," Wilander said. "You just lose a semifinal or something and then your confidence is blown and you don't win any more. It's so strange: suddenly it's over."
Yet this underestimates Djokovic's qualities. He is an unusual champion because, in contrast to the precocious Wilander , he achieved pre-eminence relatively late in his career.
In the 1980s or 90s, a tennis champion of 28 would have been drawing towards his twilight years. Yet here, too, Djokovic is coming from a different angle.
He can feed off modern sports science, plus a lifetime of flexibility training - a far-sighted move that was recommended by his childhood coach and mentor, Jelena Gencic. The upshot is that he is arguably the most durable player on the tour, as well as the best technician.
As Gilbert pointed out: "He's an incredibly young 28. He's in the prime of his career. To me, he's set to do some unbelievable damage the next couple of years."
There is at least one man, however, who seems to have accepted the harsh truths of 21st-century tennis. Andy Murray has suffered more than anyone from Djokovic's indomitability, and knows well that the only way to this Australian Open title is through the world No1's roadblock.
"It's a huge challenge," said Leon Smith, the British Davis Cup captain. "But he [Murray] has shown before that he can make adjustments, adaptations in his game. Like all players - and I am privy to seeing what Andy does - he is looking for things to challenge the top players and the top player now is Novak Djokovic."
Whether Murray's customised approach will yield results is another question, for he comes into 2016 on a run of 10 defeats from the past 11 meetings with his oldest rival. But at least, if Smith is to be believed, the world No2 has shown up in Melbourne with a plan.