Finally, the old gang is reassembling. This week, for the first time since the US Open two months ago, three of the top four players in men's tennis are in the same competition. Next week, in Paris, and later this month, in London, all four should be in the same tournament.
This is good news for fans of the game who are keen to learn the answers to several questions.
Is Djokovic primed to put an exclamation mark on the end of a marvellous season? Three successive victories would make this a season to compare to any. Can Nadal end Djokovic's dominance over him?
And can he keep the other two in his rear-view mirror?
Is Murray's rightful place in the world order ahead of Federer, as he finds himself at the moment, or behind him, which has been the previous state of affairs?
Injuries and fatigue conspired to keep no more than half of the Big Four from playing in any tournament between the US Open and Basel. Djokovic and Federer have not played at all, aside from the Davis Cup.
Murray has the most to gain in Basel. He could face Federer in the semi-finals and Djokovic in the final, and a pair of victories there could present us with another year-end question: is the Scot ready for a push for the top?