Alexander Zverev has beaten Rafael Nadal in their opening round-robin match of the ATP Finals.
The loss dents Nadal's chances of ending the year as the number one ranked tennis player in the world.
He entered the season-finale in London with an abdominal injury.
Tuesday's match sees Roger Federer, who also lost his opening encounter, take on Italy's Matteo Berrettini.
Play gets underway at 6:00 pm UAE time.


Pogacar wins third Flanders crown but faces fine for running red light
Thuram and Martinez star as Inter dismantle Roma
Silva to exit Man City at end of season, assistant manager confirms
Penalty heroics help Leeds beat West Ham to reach FA Cup semis
Pogačar wins Tour of Flanders for record-equalling third time
