Former world number one and 12-time major winner Novak Djokovic will face Spain's Roberto Bautista Agut in his first match in almost six months at the Mubadala world championships on Friday.

Bautista Agut, the world number 20 from Spain, set up the showdown against Djokovic by seeing off flamboyant young Russian Andrey Rublev 7-5, 6-2 on Thursday.

Djokovic hasn't played since retiring from his quarter-final at Wimbledon against Tomas Berdych in July with an elbow injury.

The 30-year-old will make his comeback on Friday before launching his competitive campaign as top seed at the Qatar Open next week.

Bautista Agut, 29, took advantage of the hard-hitting Rublev’s numerous unforced errors to win in 88 minutes.

Rublev was broken twice in each set and even though he saved four match points in the eighth game of the second, his aggression once again cost him as he netted a powerful forehand to end the match.

Bautista Agut has won just one of seven matches against Djokovic, now ranked at 12 in the world, in his career.

"It’s going to be great to have Novak on court again -- for everybody, for tennis, for all of us," said the Spaniard.

"I’m happy to play against him again. I played some tough matches with him and I always enjoy playing against Novak."

South African world number 14 Kevin Anderson provided the first upset of the three-day Abu Dhabi event, defeating the 10th ranked Spaniard Pablo Carreno Busta in the opening match on Thursday.

The 31-year-old Anderson has never lost to Carreno Busta on the ATP Tour, enjoying a 3-0 advantage over his rival, including a semi-final win in this year’s US Open, and he never looked in trouble with an assured 6-3, 7-6 (7/2) win.

Anderson broke Carreno Busta early in the second game of the opening set, and then his aggression paid off in the second-set tie-breaker as he earned a place in the semi-finals on Friday against world number five Dominic Thiem of Austria.

“It was a good start for me. The court here is similar to the ones in Australia and they use the same balls. I have worked hard on my game during the pre-season and to be able to put some of those things into a match situation and succeed, was a good feeling,” said Anderson as he builds towards the season's first Grand Slam in Melbourne next month.

Another highlight of the UAE tournament will be the comeback of former women’s number one Serena Williams on Saturday.

The 36-year-old American, the most successful player in the Open era with 23 Grand Slam titles, plays French Open champion Jelena Ostapenko in a match scheduled to be held before the men’s final.

Williams was last seen in action winning the Australian Open this January. She then took a sabbatical to give birth to her first child, Alexis Olympia, in September.