The six-man event is underway in Abu Dhabi as Novak Djokovic looks to get back on form after six months out with injury.
He will be the favourite if he can show his class of old with world No 1 Rafael Nadal pulling out as he looks to battle a knee problem.
Nadal’s withdrawl sees Djokovic and Austria’s Dominic Thiem as the top two seeds and through to the semi-finals.
Mubadala World Tennis Championship results
Thursday 28 December
Kevin Anderson beat Pablo Carreno Busta 6-3, 7-6
Roberto Bautista Agut beat Andrey Rublev 7-6 6-2
Mubadala World Tennis Championship schedule
Friday 29 December
Semi-Final 1: Dominic Thiem v Kevin Anderson
Semi-Final 2: Novak Djokovic v Roberto Bautista Agut
Saturday 30 December
Third Place Play-Off