Organisers of the world's biggest tournaments say they will not make the same mistakes as they reopen the sport and seek to keep the players safe.
World number eight Williams, who captured the first of her six US Open titles two years before her 17-year-old opponent was born, spent the first half of the match trying to find her rhythm but when she did she was off to the races.
Federer has been brandishing an aggressive style of play, forcing the action and rushing in to half-volley weak second serves to forge an advantage.
Serena Williams has been vulnerable this Grand Slam season but unbeaten in the year's first three major championships.
Simona Halep did something no one else was able to do against Serena Williams at the US Open on Wednesday but still could not stop the world number one from advancing to the semi-finals of the year's final Grand Slam.
The US Open has said it regrets that French player Alize Cornet was given a warning for removing her shirt during a match following complaints that the decision was sexist.
Five-time Grand Slam champion Sharapova, who won at Flushing Meadows in 2006, struggled with her serve at times in the opening set but Schnyder failed to take full advantage.
World number two Rafael Nadal confirmed on Tuesday that he will not defend his US Open crown this year at Flushing Meadows as organisers released the singles entry list for the Grand Slam. Spain's Nadal had said in June that he had reservations about travelling to the U.S. amid the COVID-19 pandemic and he joins women's world number one Australian Ash Barty in skipping the tournament due to COVID-19 concerns.
Defending champion Marin Cilic had to battle hard before beating Kazakhstan's Mikhail Kukushkin 6-7, 7-6, 6-3, 6-7, 5-1 in their 3rd round match of the US Open on Friday.
Roger Federer launched his bid for an 18th grand slam title with a workmanlike 6-3, 6-4, 7-6 (4) win over Marinko Matosevic to ease into the second round of the US Open on Tuesday, with NBA great Michael Jordan leading the cheering.
Tennis must consider shortening matches in a bid to engage with a younger fanbase and avoid losing television viewers, according to former ATP Player Council president and doubles specialist Eric Butorac.
Images from Day 8 of the 2021 US Open in New York on Monday.
The final will pit power against power when Andreescu takes on her childhood hero Williams, who claimed her first US Open title in 1999 before Andreescu was even born.
After a flawless first set from Mertens the tide turned in Andreescu's direction in the second when she fired a cross-court forehand winner to break the Belgian at love and take a 4-2 lead.
Prajnesh Gunneswaran got a taste of high-level tennis in his first-round exit from the US Open, losing to world number five Daniil Medvedev in 84 minutes, in New York, on Monday.
Rafael Nadal has pulled out of next week's ATP Tour Finals in London due to injury, so Novak Djokovic will end the year as world number one having returned to the top of the rankings on Monday.
World number one Novak Djokovic was sensationally disqualified in the US Open fourth round on Sunday after striking a line judge with a ball following a point during the first set of his match against Spain's Pablo Carreno Busta.
A summary of Wednesday's action at the US Open.
The World number was pitted against Spaniard Albert Costa in Wednesday's draw.
The former US Open champion has withdrawn from this year's tournament because of a lingering wrist injury.
Sania lost to third-seed Sesil Karatantcheva of Bulgaria in the finals of the Bernstein Tennis Tournament.
47-year-old Martina Navratilova and Lisa Raymond were also picked in the U.S. team for their Fed Cup first-round tie against Slovenia.
The German sixth seed, who has not won a title since winning at Flushing Meadows last year, never got into the match against the 2016 WTA newcomer of the year.
'I have seen myself as nothing but an Indian,' Prakash Amritraj tells Ashish Magotra.
The 2003 US Open will be played at the USTA National Tennis Center in Flushing, New York, from August 25 to September 7.
Serena Williams has never been one to approach the net until it is time to exchange post-match pleasantries with an opponent but on Thursday she broke from tradition and it paid off with a trip to the U.S. Open final.
IMAGES from the US Open matches played on Day 1 at the Flushing Meadows in New York on Monday.
Flavia Pennetta beat unseeded Italian compatriot and childhood friend Roberta Vinci 7-6(4) 6-2 to win the US Open women's singles title on Saturday.
World number two Roger Federer launches his bid for a sixth US Open title, and his first since 2008, with a first-round match against Argentina's Leonardo Mayer at the Arthur Ashe Stadium on Tuesday.
Seven years after their first Grand Slam final meeting, Novak Djokovic and Roger Federer stand on the verge of a third showdown at the highest level.
Sumit Nagal lived a dream when he took on one of the greatest players of all time at a packed Arthur Ashe stadium in a US Open first-rounder.
Switzerland's Stanislas Wawrinka rose to the occasion once again to beat Novak Djokovic with a scintillating display to win his first US Open and third Grand Slam title.
'I had to learn to be patient. I am a different player and a different person than I was three years ago. I still believe I can repeat that 2015-2016 streak when I won four slams in a row, I wouldn't be here if I didn't.'
Images from Day 7 of the 2021 US Open in New York on Sunday.
'Almost three hours. It's midnight now. Credit to John for putting up a great battle'
Overpowers Svitolina to reach second straight US Open final
Nadal claimed his second grand slam title of the year -- having won the French Open in June -- beating No. 28 seed Kevin Anderson of South Africa in straight sets 6-3, 6-3, 6-4 at Arthur Ashe Stadium in Flushing, on Sunday.
Nadal will next face Ukraine's Alexandr Dolgopolov.
