The USTA confirmed that a number of players were now being tested on a daily basis, rather than every four days NEW YORK: Top seeds including Novak Djokovic overcame eerily quiet stands as a "weird," spectator-free US Open started Monday with heightened safety protocols for some players following a positive COVID-19 test. Several competitors were placed in what one of them described as a "bubble within a bubble" after France"s Benoit Paire was withdrawn from the men"s draw Sunday for testing positive for coronavirus. "It was made clear that the infected player was not adhering to the health protocols that have been approved by the State of New York," a spokesperson for the United States Tennis Association told AFP. A person familiar with the matter said Paire had been lax about wearing a face covering. Djokovic and top women"s seed Karolina Pliskova were among the big names to shrug off the deathly quiet at Flushing Meadows and progress to the second round of the first Grand Slam of the COVID-19 era. Match-winning points went uncheered, ball persons wore masks, and players had to reach for their own towels in a tightly controlled environment that made for a opening day Slam unlike any other. "The conditions are strange, we miss the fans," said France"s Kristina Mladenovic after a 7-5, 6-2 win over American Hailey Baptiste. Mladenovic was one of several players forced to adhere to stricter safety measures after compatriot Paire was withdrawn. Several competitors including Richard Gasquet, Adrian Mannarino and Edouard Roger-Vasselin had been in contact with Paire, according to French sports publication L"Equipe, leading to doubts about their participation. The USTA confirmed that a number of players were now being tested on a daily basis, rather than every four days. They are now also only allowed to leave their hotel room to travel to the US National Tennis Center. Previously they had been allowed in communal areas. "We got some bad news two days ago and since then I"ve been living in a nightmare," said 30th seed Mladenovic. "I wasn"t even sure if I would able to play. We"ve been in a bubble inside a bubble. So I"m very grateful that we were able to play today," she added. Paire meanwhile was preparing to leave the tournament questioning the protocols put in place in New York. "I"m fine for now I have no symptoms .. I hesitate to tell what is really going on in this Fake Bubble," Paire wrote on Instagram. Djokovic defeated unheralded Damir Dzumhur of Bosnia-Herzegovina 6-1, 6-4, 6-1 as he launched his bid for an 18th Grand Slam with a win at an Arthur Ashe Stadium devoid of 23,000 screaming fans. Pliskova made light work of 145th-ranked Ukrainian Anhelina Kalinina 6-4, 6-0 in one of the early matches. And German Angelique Kerber, the 2016 US Open champion, also progressed to the second round, thanks to a tightly fought 6-4, 6-4 victory against Australia"s Ajila Tomljanovic. "It"s a little bit weird to play without fans and without the support and the atmosphere on the center courts," Kerber said. There was disappointment for US starlet Coco Gauff, the 16-year-old who lit up Wimbledon last year with a run to the fourth round. Gauff fell at the first hurdle, losing to Latvia"s Anastasija Sevastova 6-3, 5-7, 6-4. In the men"s draw, fifth seed Alexander Zverev was made to work hard in a three-hour-long tussle with 2017 finalist Kevin Anderson, the German ultimately prevailing 7-6 (7/2) 5-7, 6-3, 7-5. Fourth seed Stefanos Tsitsipas eased through with a 6-2, 6-1, 6-1 win over Spain"s Albert Ramos-Vinolas. The absence of defending champion Rafael Nadal and Swiss legend Roger Federer gives Djokovic a prime opportunity to gain ground on his rivals in the chase for the all-time men"s Grand Slam singles title record. Djokovic currently has 17, behind Nadal on 19 and Federer on 20.