As the U.S. Open got underway amid the pandemic today, seven players were put in what one described as a "bubble in the bubble" because they were in contact with Benoit Paire, the Frenchman dropped from the tournament after testing positive for the coronavirus, a person with knowledge of the situation told The Associated Press.

The seven players were not identified to the AP by the person, who spoke on condition of anonymity because the U.S. Tennis Association has not announced the names of anyone involved.

But two players from France acknowledged their involvement: Kristina Mladenovic, who is seeded 30th in women's singles, and Edouard Roger-Vasselin, who is entered in men's doubles.

"We cannot confirm any numbers or names of players due to health laws," tournament director Stacey Allaster said. "In the case of Edouard Roger-Vasselin, as he has publicly stated he is one of a select number of players in the enhanced protocol plan, I can confirm that he is one of those players."

Mladenovic acknowledged after her first-round victory on Day 1 at the Grand Slam tournament that her movements were restricted because she spent time with Paire. She said she practiced with Paire for about an hour and spent 30-40 minutes playing cards with him and others in the lobby of a hotel being used by the USTA for what it has called a "controlled environment."

"I am basically in a new 'bubble in the bubble,' so there's not very much I'm allowed to do, which makes it tough for me to compete and mentally be kind of fresh and ready," said Mladenovic, who doubled over and let out a loud yell after beating Hailey Baptiste of the United States 7-5, 6-2.

Asked to describe what she can and cannot do, Mladenovic chuckled.

"Let's make it simple: I'm allowed to play my match," she said. "Literally, not allowed to do anything else."

Allaster said the players potentially exposed to the virus because of contact with Paire now must be tested daily for COVID-19, instead of every four days.

Mladenovic said she was told she can spend time with her brother but "no one else," and has been banned from working out at the gym and "any other facilities that have been put in place for the players."

"It's pretty tough for me to accept that ... because it's not like I'm part of (Paire's) entourage," Mladenovic said.

Paire is one of two people to have tested positive so far and the only player. The other was a fitness trainer; two players he was in contact with — Argentina's Guido Pella and Bolivia's Hugo Dellien — were kicked out of the Western & Southern Open, the tournament that preceded the U.S. Open at the same site.

As for the difference between those two players who potentially were exposed being dropped from the field and this more recent group remaining eligible to play, Allaster said: "Each case is determined by the facts and circumstances. We will not discuss how the two are specifically different because this is protected health information."

The new limitations on Mladenovic were jarring for her to deal with, she said — and a reminder, as if there weren't already so many others, of the challenges of attempting to stage a major international sports event these days. Monday's matches gave a taste of what this U.S. Open will be like: mostly empty, mostly quiet courts with no fans and only handfuls of people present.

There are full complements of line judges only at two courts; the rest are relying on a chair umpire and electronic calls. Everyone is supposed to wear masks unless they're playing. Players have to walk to get their own towels instead of having them handed over by ball people.

There were about 15 people in the seats at 14,000-capacity Louis Armstrong Stadium for the start of 2016 U.S. Open champion Angelique Kerber's 6-4, 6-4 victory over Ajla Tomljanovic.

When Kerber broke to take the first game, one person — her coach — clapped.

"It's kind of a little bit the feeling when you play, like, practice matches," Kerber said.

There were seven people in Court 11′s bleachers — six after one left in the middle of the seventh game — for No. 27 Borna Coric's 7-5, 6-3, 6-1 win over Pablo Andujar, whose complaint to chair umpire Fergus Murphy about serve-clock management was easily audible.

Andujar: "In my opinion, it's too fast. ... Can you please give a little bit more (time)?"

Murphy: "No."

Andujar: "No?"

And other than some fake, piped-in crowd noise and loud music blaring on changeovers, there was almost no sound at all in cavernous Arthur Ashe Stadium for its first match of the 2020 tournament, No. 1-seeded Karolina Pliskova's 6-4, 6-0 victory over Anhelina Kalinina.

Said Pliskova: "I was like, 'Should I cheer myself?'"

Two seeded men exited in the afternoon.

No. 18 Dusan Lajovic lost to Egor Gerasimov 6-1, 4-6, 6-4, 6-4.

No. 9 Diego Schwartzman was hampered by cramps, wasted a big lead and was beaten by Cameron Norrie 3-6, 4-6, 6-2, 6-1, 7-5, then went out without a shirt to watch a match in Ashe — all seeded players were given a normally high-priced suite to use as a personal lounge.