Stefanos Tsitsipas was booed by the crowd for yet another off-court break at the US Open after dropping a set during his second-round victory over Adrian Mannarino. Unbothered by the heckling, or by the criticism he received from Andy Murray after taking breaks while beating him two days earlier, Tsitsipas maintained out that he's doing nothing that violates any regulation. “If I break a rule, sure, I’m guilty. I agree; I’m not doing something right,” Tsitsipas said after hitting 27 aces and beating Mannarino 6-3, 6-4, 6-7, 6-0 with the roof closed at Arthur Ashe Stadium because of heavy rain from remnants of Hurricane Ida. “If I’m staying within the guidelines, then what’s the issue?” Tsitsipas took a toilet break that created an eight-minute delay between the end of the third set and start of the fourth. His return was greeted by fans voicing their displeasure — certainly aware that three-time major champion Murray called “nonsense” in their first round match. Murray also said he “lost respect” for Tsitsipas, who is seeded No 3 at Flushing Meadows and was the runner-up at the French Open in June. Asked about the spectators' boos, Tsitsipas replied: “I haven’t done anything wrong, so I don’t understand. The people love the sport; they come to watch tennis. I have nothing against them. I love the fans. "But some people don’t understand. That’s all. They don’t understand. They haven’t played tennis at high level to understand how much effort and how much difficult it is to do what we are doing. Sometimes we need a short break to do what we have to do.” Mannarino agreed that the fault lies with the rule book, not Tsitsipas. “He's not doing anything wrong,” he said. “I think the rule is wrong.” The US Open is the only Grand Slam tournament where Tsitsipas has yet to reach the fourth round. He's been that far at Wimbledon and to the semifinals at the Australian Open, in addition to his run at Roland Garros before losing to Novak Djokovic in the final. Now Tsitsipas will face 18-year-old Carlos Alcaraz of Spain for a berth in the fourth round. “I want to play the best of my game against him,” Tsitsipas said. “I see him as a potential contender in the future for Grand Slam titles and other big events.”