Novak Djokovic keeps alive sixth Dubai title bid after thrilling win over Karen Khachanov

Novak Djokovic issued an ominous warning to his quarter-final rivals at the Dubai Duty Free Tennis Championships after the world No 1 produced another fine display to defeat Karen Khachanov in the second round.

Inside a raucous, full-capacity Centre Court on Wednesday evening, Djokovic came through an absorbing encounter 6-3, 7-6 and will face Jiri Vesely for a place in the semi-finals after the Czech qualifier stunned Spanish eighth seed Roberto Bautista Agut over on Court One.

Before arriving in Dubai, Djokovic had not played a competitive match since representing Serbia at the Davis Cup in November, his hopes of defending his Australian Open title dashed on the eve of the tournament when he was controversially deported. But there have been no signs of rust and it will take something special to prevent the 34-year-old Serb in this form from marching to a sixth Dubai title.

"It was a fantastic test. I really enjoyed the atmosphere as well tonight on the court," Djokovic said.

It didn't look like it would be much of a test when the top seed led by a set and 4-2, but Khachanov threw caution to the wind and unloaded some big shots to force his way back into the contest, earning his break back to level at 4-4. The set, and ultimately the match, was decided in a tiebreak and Djokovic clinched the victory with a stunning return on the Khachanov serve.

"You always prefer to win in straight sets without getting too stressed about the match, but I actually like the fact that I dropped my serve," the 20-time major winner said. "I allowed him to come back to the match and he started playing better in the second set, hitting the spots with the serve. We were going toe-to-toe. Then I played the best possible tiebreak that I could