Rafael Nadal and Roger Federer can set up a dream climax to the 2017 season at the ATP World Tour Finals, but organisers are sweating on the Spaniard's fitness and a new crop are itching to spoil the party. The two all-time greats get star billing in London after each won two Grand Slams and locked down the top two rankings spots as Novak Djokovic and Andy Murray had injury-plagued seasons to forget.

This file photo taken on November 02, 2017 shows Spain's Rafael Nadal returning the ball to Uruguay's Pablo Cuevas during the 1/8 round at the ATP World Tour Masters 1000 indoor tennis tournament in Paris. Rafael Nadal said on November 10, 2017, he "hopes" to be ready for his opening match at the ATP Finals but admitted he has not been training at 100 per cent after an injury scare. Pic/AFP