LONDON Nov 8 Everything is still up for grabs when Group A concludes at the ATP World Tour Finals on Friday.
The round-robin format has once again had fans, organisers, media and even players scratching their heads at the various scenarios that will decide the top two in the group.
Novak Djokovic, who has won both his matches against Jo-Wilfried Tsonga and Andy Murray, could still miss out while Tsonga, beaten in both of his, could yet make the semis.
Tournament organisers the ATP issued a 10-point list of possible Group B outcomes on Thursday, depending on what transpires on Friday when Murray faces Tsonga after Djokovic takes on Tomas Berdych.
Here are the basic permutations:
* Djokovic will qualify for the semi-finals if he beats Berdych or loses in three sets.
* Murray will definitely go through if he beats Tsonga in straight sets.
* Berdych will reach the semi-finals if he beats Djokovic in two sets, although even if that did happen Djokovic would survive if Tsonga got a set off Murray.
* Tsonga's hopes will already be gone when he walks on court if Berdych manages to win at least a set in the day's first singles against Djokovic. (Reporting by Martyn Herman, editing by Pritha Sarkar)
Our top photos from the past week.