Top-ranked Novak Djokovic held on to beat Czech qualifier Tomas Machac 6-3 3-6 7-6 (1) at the Dubai Championships in his first match since winning his 10th Australian Open title.
Djokovic's first-round victory on Tuesday 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-equaling 22nd Grand Slam singles title. He led 4-1 in the third set 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, is 13-0 this season and extended his overall winning streak to 18 matches.
A presentation was held after Tuesday's match to recognize 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 winning streak to 10 matches.
Fourth-seeded Felix Auger-Aliassime defeated Maxime Cressy 7-6(4) 3-6 6-3 and Botic van de Zandschulp beat sixth-seeded Karen Khachanov 7-5 6-2.