Novak Djokovic said he is enjoying the pressure of being the overwhelming favourite to win the US Open after getting his campaign under way with a routine first round win over Damir Dzumhur on Monday night. World No 1 Djokovic lost his way a bit in the second set but rallied for a 6-1, 6-4, 6-1 victory on Arthur Ashe Stadium that extended his extraordinary winning streak to 24 matches this year. The absence of fans because of the coronavirus pandemic perhaps exaggerated his testy exchange with the umpire, the angry roar he emitted after sealing the second set, and a bit of back-and-forth with his box. For Djokovic, though, it was just all part of his make-up as a 17-time Grand Slam champion. "You care about winning a tennis match, obviously you're a professional," the top seed said on court after setting up a second-round meeting with Briton Kyle Edmund. "If I didn't care, I wouldn't be here. This is how I play, I play with a lot of intensity and try to bring a lot of energy to the court." In the absence of the two other men vying for the title of the greatest male player of the modern era, Roger Federer and Rafa Nadal, Djokovic is widely expected to win a fourth US Open crown. That, combined with maintaining the prospect that he might go through the year unbeaten, could weigh on a player with less mental strength. "I know pressure is a privilege, pressure is part of what we do," Djokovic said. "I try to embrace it. I know what I need to do and how to behave, how to make myself calm and composed and focused on what really needs to be done." Earlier, fifth seed Alexander Zverev was made to work hard as he progressed into Round 2 following a three-hour-long tussle with 2017 finalist Kevan Anderson. The German, seeking his first Grand Slam title, took the first set on a tie-break 7-6 before losing the second 7-5 in an eerily empty Arthur Ashe Stadium. Ultimately, the 23-year-old fifth seed proved too much for the South African veteran, winning the third set 6-3 and the fourth 7-5. "I am actually quite happy with a first round like that," said Zverev, who reached his first Grand Slam semi-final at the Australian Open earlier this year. "Kevin is not someone you usually play in a first round. This is a fourth round, quarter-final, semi-final match normally against him. I am extremely happy to be through." Stefanos Tsitsipas eased into the second round with a straight-sets win over Spain's Albert Ramos-Vinolas. The Greek fourth seed needed just one hour and 38 minutes to dispose of the world No 41, 6-2, 6-1, 6-1. The 22-year-old Tsitsipas will play American wildcard Maxime Cressy after he defeated Slovakian Jozef Kovalik 6-1, 2-6, 6-4, 6-4. Britain's Cameron Norrie enjoyed one of the day's most impressive wins, charging back from two sets down to sink Argentine ninth seed Diego Schwartzman 3-6, 4-6, 6-2, 6-1, 7-5. Elsewhere in the men's draw, 12th seed Canadian Denis Shapovalov required four sets to overcome US wildcard Sebastian Korda. The 21-year-old left-hander won the first set 6-4 before losing the second by the same score. But he rallied to win the next two 6-3, 6-2. "Playing without the fans is definitely different," Shapovalov said. "You know, I love to use the fans to kind of pump me up. So I had to do that within myself. But I'm getting familiar with it pretty quick." Frenchman Gilles Simon enjoyed a straightforward victory over Egypt's Mohamed Safwat. The 35-year-old triumphed 6-1, 6-4, 6-4. Adrian Mannarino, also of France, defeated Italy's Lorenzo Sonego 6-1, 6-4, 2-6, 6-3 in a match that lasted two hours and 41 minutes.