When the match began it was Federer who surprisingly looked intimidated under the Arthur Ashe Stadium lights as he sprayed errors all around the court but the Swiss great woke from his slumber in time to turn the match resoundingly in his favour.
Norway's Casper Ruud harnessed his mighty forehand to reach his second Grand Slam final this year by beating Russia's Karen Khachanov 7-6(5), 6-2, 5-7, 6-2 at the US Open, keeping alive his hopes of reaching the top of the world rankings.
This will be her first appearance at the tournament since she was ousted in the second round in 2017.
A summary of Thursday's action at the US Open.
The French Tennis Federation, in a surprise move, switched the claycourt Grand Slam tournament to Sept. 20-Oct. 4 from its May start due to the novel coronavirus outbreak. The new Roland Garros dates clashed with the Sept. 25-27 Laver Cup. The tournament will now be held from Sept. 24-26 in 2021.
Four times now, twice at Wimbledon (2018, 2019) and at the US Open (2018, 2019) Serena Williams has come agonizingly close to that 24th Grand Slam only to fall at the final hurdle.
Bianca Andreescu, 19, the first Canadian to win a major in the professional era, prevented Serena Williams from equalling Margaret Court's record of 24 Grand Slam singles titles.
Serena Williams appeared to suggest last month that she would end her playing career at the U.S. Ope
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.
Geopolitical tensions simmered at the US Open on Thursday as Ukrainian Marta Kostyuk refused the customary handshake at the net when Belarusian Victoria Azarenka defeated her 6-2, 6-3 in the second round.
Maria Sharapova's US Open preparations took a major blow with the Russian World No 2 forced to withdraw from next week's WTA event in Toronto.
Marin Cilic and Kei Nishikori will meet in the semi-finals at the Citi Open in Washington on Saturday, their first encounter since the final of last year's US Open.
Both players burn with heaps of motivation to hoist the winner's trophy at Arthur Ashe Stadium in the last grand moment of the 2015 slam season.
Serena Williams overpowered German Carina Witthoeft 6-2, 6-2 to set up a third-round clash with big sister Venus at the US Open on Wednesday.
Building the stamina to consistently survive the rigours of playing five-set matches will top Andy Murray's agenda as the former US Open champion, who has undergone two hip surgeries, plots the revival of his career.
Images from Day 3 of the 2020 US Open in New York, on Wednesday.
Konta first British woman in US Open last 16 since 1991
Novak Djokovic kept his unbeaten streak in 2020 alive as he survived a terrible start to defeat Milos Raonic 1-6, 6-3, 6-4 in the final of the Western & Southern Open on Saturday.
Top seed Novak Djokovic made quick work of Tennys Sandgren at the Western and Southern Open on Tuesday, never dropping serve en route to a 6-2, 6-4 win over the American, while big-serving Milos Raonic enjoyed a straight sets win over Andy Murray.
Images from Day 5 of the US Open in New York on Friday
British qualifier Emma Raducanu beat Canada's Leylah Fernandez 6-4 6-3 in a battle of two unseeded teenagers to win the U.S. Open women's title on Saturday.
Indian tennis ace Sania Mirza stormed into the mixed doubles semifinals besides reaching the doubles quarterfinals, but compatriot Leander Paes exited the US Open with unexpected defeats in both his events.
Stan Wawrinka, who captured his maiden US Open title and first grand slam trophy of the year after defeating world number one Novak Djokovic, is unable to contain his excitement.
'Tired' Kei Nishikori takes positives out of Open despite loss.
World number one Novak Djokovic has said participating in the US Open would be an impossible task due to the "extreme" COVID-19 protocols in place for the tournament at Flushing Meadows. The US Open, scheduled to begin on August 31, will be the first Grand Slam to be played after the coronavirus pandemic suspended the season in March. The French Open was postponed to September while the Wimbledon championships was cancelled.
Federer dismisses Nadal's suggestion to play ATP Finals on clay
'I am playing tennis because I love to play tennis'
Andreescu's win over Bencic also meant she became the first Canadian woman to make the US Open final, where she faces Serena Williams, who is chasing a record-equalling 24th Grand Slam single title.
IMAGES from Day 9 of the US Open matches played on Tuesday
Romania's Italian Open winner Simona Halep, Spain's Garbine Muguruza and US Open semi-final foe Victoria Azarenka of Belarus present a major challenge for Serena Williams at the upcoming French Open.
Karolina Pliskova showed the steel of a world number one as she fought off a match point to claim a riveting 3-6, 7-5, 6-4 comeback win over Zhang Shuai in the US Open third round.
Federer looked more relieved than overjoyed when Tiafoe's forehand found the net on match point to keep his hopes of a 20th grand slam title alive.
Victoria Azarenka's return to the top has been a long road full of setbacks and challenges but she knuckled down, swallowed her ego and now finds herself back in a Grand Slam final after a seven-year absence.
Steady rain hit the US Open on Monday, washing out the last match on Arthur Ashe Stadium court featuring five-time champion Roger Federer.
Time is running out for Serena to reach the career milestone that has become one of the sport's longest running storylines.
Serena Williams' career has been so astonishing that it could fuel umpteen movies
Kristina Mladenovic had complained saying she felt like she was being treated like a prisoner after she was placed inside a 'bubble within a bubble' despite 'thirty negative tests'.
Defending champion Naomi Osaka of Japan was upset 7-5, 6-4 by Belinda Bencic in the fourth round at the US Open on Monday as the Swiss reached the quarter-finals for the second time.
Osaka, 20, shot to international fame on Saturday when she defeated 36-year-old American Serena Williams at Flushing Meadows to become the first Japanese player to claim a Grand Slam singles crown.
