The unseeded Bencic, who also beat former world number ones Caroline Wozniacki and Ana Ivanovic in Toronto, wore a look of disbelief after the 18-year-old's forehand winner whizzed past Williams to seal the match.
The 24-year-old, who has yet to win a Grand Slam title, was in stunning form as he defeated Russian Karen Khachanov 6-3, 6-1 to become the first German man to win a singles Olympic gold.
Former French Open champion Jelena Ostapenko is the latest player to withdraw from the US Open, organisers of the tennis Grand Slam confirmed on Monday.
Summary of sports events and persons who made news on Monday.
Switzerland's Belinda Bencic became the first teenager in seven years to reach the top 10 of the WTA rankings after she climbed to ninth in the world on Monday.
Eighth seed Jabeur faced a tougher time against Russian Gracheva as she survived a double break in the decider to set up a meeting with Olympic gold medallist Belinda Bencic, who got the better of Karolina Muchova 6-3, 4-6, 7-5.
Carlos Alcaraz's US Open preparations suffered a setback on Friday as the world number one fell to American Tommy Paul
IMAGES from all the action on Day 7 of the US Open played at the USTA Billie Jean King Tennis Center at Flushing Meadows in New York on Sunday.
Bencic broke Aiava at love to open the match, one of the six break points she converted, and was never really tested as the 18-year-old Australian made 24 unforced errors.
- At 18 years and 109 days, Bencic is the youngest player to win a premier-level title since Caroline Wozniacki won in New Haven almost seven years ago - Uzbek Istomin wins men's title
Novak Djokovic eased into the last four with a commanding performance over Japan's Kei Nishikori but world number two Daniil Medvedev bowed out of the men's singles at the Tokyo Olympics.
Tennis matches at the Ariake Tennis Park will begin from 3pm local time (0600 GMT) from Thursday, governing body International Tennis Federation said after requests from players who had struggled in the stifling weather.
World number one Naomi Osaka lost in three sets to unseeded Swiss Belinda Bencic in the Madrid Open quarter-finals on Thursday as Simona Halep, Sloane Stephens and Kiki Bertens completed the final four line-up.
IMAGES from Day 5 of the Australian Open in Melbourne, on Friday.
Italian seventh seed Jannik Sinner beat Tommy Paul to set up a Canadian Open final clash with Australia's Alex De Minaur
A long measure of Grand Slam patience paid off for Peng Shuai of China, who reached the semi-finals of the US Open on Tuesday by routing Swiss teenager Belinda Bencic 6-2, 6-1 in the Flushing Meadows heat.
Images from Day 9 of the 2023 Wimbledon Championships at The All England Lawn Tennis Club in London on Tuesday.
Switzerland won their third Hopman Cup on Saturday as Roger Federer and Belinda Bencic beat Germany's Alexander Zverev and Angelique Kerber 4-3(3), 4-2 in the deciding mixed doubles to secure a 2-1 victory in the final at the Perth Arena.
The 23-year-old, who this week became the first Australian woman to reach the top of the rankings since 1976, must survive a rough-looking path if she is to claim back-to-back Grand Slams having won her first at this month's French Open.
Osaka, 21, said she lacked maturity when as a relative unknown player she won the tournament last year to kick off her meteoric rise through the rankings.
Holder Elina Svitolina will face world number one Ash Barty in the end-of-season WTA Finals showpiece on Sunday after they got past Belinda Bencic and Karolina Pliskova respectively in the semi-finals at Shenzhen Bay Sports Centre.
The 2013 Wimbledon finalist Sabine Lisicki set a new world record.
The French Open will be able to welcome only 1,000 people a day, including players, staff and organisers, down from the 5,000 spectators it had hoped for,
American tennis ace Serena Williams has maintained her No 1 spot, while German Angelique Kerber has slipped to the third in the latest women's tennis world rankings issued by the WTA.
US Open: Serena ready for Svitolina challenge
Former World No 1 Caroline Wozniacki and rising Swiss talent Belinda Bencic have withdrawn from the French Open due to injuries, the WTA said.
Simona Halep has moved back to the top five in the latest women's tennis world rankings issued by the WTA, after clinching her first title in over a year at the Madrid Masters.
Kyrgios added that he had been in communication with Tennis Australia chief executive Craig Tiley and United Cup tournament director Stephen Farrow about his injury.
A clash of generations will decide the US Open on Saturday with Serena Williams taking a fourth crack at Grand Slam history against teenager Bianca Andreescu, who was not even born when the American lifted her first Flushing Meadows trophy.
Her last Grand Slam triumph came in 2017 and she has not won a WTA title since lifting the ASB Classic in Auckland at the start of the 2020 season.
Agnieszka Radwanska continued her pre-Wimbledon tune-up by reaching the final of Eastbourne grasscourt tournament with a 6-1, 6-7(3), 6-2 win over America's Sloane Stephens on Friday.
Williams, 37, said "it's not about what we can do it's what we MUST do as working moms and working dads".
Former world number one Simona Halep stepped up her French Open preparations with a 6-4, 6-4 victory over American Coco Gauff to march into the quarter-finals of the Madrid Open on Monday while Andy Murray won on clay for the first time in five years.
Images from Day 6 of the 2023 Australian Open at Melbourne Park on Saturday.
Other nominees for the prize are Angelique Kerber (Germany), Petra Kvitova (Czech Republic and Caroline Wozniacki (Denmark).
Wozniacki blasts WTA Tour for forcing her to play in the tournament without proper preparation.
Bianca Andreescu is the first Canadian to win a major in the professional era.
Villa manager Gerrard to sit out two games after positive COVID test.
Singapore Slammers beat Indian Aces 27-21 in what turned out to be a dress rehearsal for the final of the International Premier Tennis League (IPTL), which the two teams will be vying for $1 million prize money.
Spain are the first nation to join exempted France, Australia, Czech Republic and hosts Hungary in the revamped finals taking place in April.