Djokovic holds on in Dubai, takes winning streak to 18

Top-ranked Novak Djokovic has held on to beat Czech qualifier Tomas Machac 6-3 3-6 7-6 (7-1) at the Dubai Championships in his first match since winning his 10th Australian Open title.

Djokovic's first-round victory came a day after the 35-year-old Serb broke the record for the most time spent at No.1 in the professional tennis rankings by a man or woman.

Djokovic was a bit rusty on his return from a few weeks off after overcoming a hamstring problem in Australia to win his record-equalling 22nd grand slam singles title.

He led 4-1 in the third set on Tuesday before the 130th-ranked Machac forced a tiebreaker.

"He was giving me all kinds of trouble, but I guess when it mattered I found another gear," Djokovic said in his on-court interview.

"I haven't played much tennis (recently), so I'm hoping as the tournament progresses I can raise the level."

Djokovic, who next faces Tallon Griekspoor of the Netherlands, is 13-0 this season and extended his overall winning streak to 18 matches.

A presentation was held after Tuesday's match to mark Djokovic's 378th week in the ATP's top spot, surpassing Steffi Graf's 377 leading the WTA.

"As a young boy growing up in Serbia, I dreamt of two things - winning Wimbledon and being No.1 in the world.

"I've been blessed to achieve both of my childhood dreams, several times," he said.

Also on Tuesday, third-seeded Daniil Medvedev beat Matteo Arnaldi 6-4 6-2 to extend his own winning streak to 10 matches.

Fourth-seeded Felix Auger-Aliassime defeated Maxime Cressy 7-6 (7-4), 3-6, 6-3, while Botic van de Zandschulp beat sixth seed Karen Khachanov 7-5, 6-2.

Aussie qualifier Chris O'Connell faces a last-16 clash with No.7 seed Alexander Zverev after beating Finland's Emil Ruusuvuori 7-5 6-4.