World No 5 Roger Federer's possible records aside, it is the first time since 2003 that the semis have featured four men outside the top four in the world rankings.
News of all that's transpired on and off the tennis courts
Switzerland's Roger Federer claimed a record-equalling sixth Australian Open title with a 6-2, 6-7(5), 6-3, 3-6, 6-1 victory over Croatia's Marin Cilic on Sunday.
Novak Djokovic is still uncertain whether he will take part in the 2022 Australian Open but will soon make a decision, the World No 1 said after Serbia's 2-1 defeat by Croatia in the Davis Cup semi-finals on Friday.
Marin Cilic, thrashed by Roger Federer in straight sets in Sunday's Wimbledon final, said he had been suffering from a blister in his foot during the showpiece clash.
World No 1 Rafael Nadal, who is hoping to recover from a knee injury to play in the season-ending showpiece, heads the other group and will face Belgian David Goffin, Bulgarian debutant Grigor Dimitrov and Austrian Dominic Thiem.
Zverev twisted his ankle as he tried to retrieve a shot in the 12th game of the second set
Spanish teenager Carlos Alcaraz beat Norway's Casper Ruud 6-4, 2-6, 7-6(1), 6-3 in the men's singles final at the US Open on Sunday to win his maiden Grand Slam title and rise to world number one for the first time.
Three-time US Open champion Djokovic, who comes into the tournament having won his fifth Wimbledon title, is followed in the seedings by 2017 winner Rafael Nadal.
UAE Royals returned to winning ways by posting a thrilling 26-21 victory over Manila Mavericks on Day 2 of the Singapore leg of the International Premier Tennis League.
'It's always going to be ... in the years to come, 'oh, you know that guy won a US Open in 2020 without fans'. I don't think it's going to have that weight... It wouldn't be the best scenario.'
World number six Marin Cilic will be the biggest international star in the singles field at the upcoming Chennai Open, the only ATP 250 tournament in India.
Wimbledon finalist Marin Cilic said he had a "big mountain to climb" to defeat seven-time champion Roger Federer, but that winning the title would mean the world to him.
Inspired Cilic vs 'tired' underdog Muller
Earlier in the day, Croatia's Borna Coric said he has tested positive for coronavirus. He became the second player to test positive for COVID-19 after Bulgaria's Grigor Dimitrov.
Cilic, eliminated after two three-set losses, was hoping to end his year on a high in the city where his Wimbledon dream was ended in this year's final by Federer - the Croatian sobbing on court after suffering blisters.
Second seed Novak Djokovic tackles Croatia's Marin Cilic in the third round of the French Open on Friday as his attempt to win the only grand slam title to elude him gathers pace.
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.
Juan Martin del Potro took advantage of an error-strewn Marin Cilic performance to beat the defending champion for a seventh time in a row on Saturday to set up another Swiss Indoors final showdown with Roger Federer.
Tomas Berdych rebounded from an opening defeat to revive his hopes at the ATP World Tour Finals by demolishing Croatia's Marin Cilic at the O2 Arena on Wednesday.
Russia took an unassailable 2-0 lead over Croatia in the Davis Cup final in Madrid on Sunday to secure their third title and first in 15 years, as Daniil Medvedev outlasted Croatian Marin Cilic 7-6(7), 6-2.
'I would say winning the US Open has helped me for all these grand slams I have played so far, and I believe the rest of my career' 'It's great for me to hear that even he, and a lot of players around, even ex-players, when they were looking before the tournament started, that they were seeing me as a player that could go quite deep (into the tournament)'
Wielding a potent backhand and renowned for his fitness, the serve-volleying Cooper beat Neale Fraser for his maiden Grand Slam title at the 1957 Australian Championships and again for the Wimbledon trophy the following year.
The 20-time Grand Slam champion smoothly pressed the accelerator to take the tiebreak and outclassed Cilic in the fourth set to claim a 6-2, 2-6, 7-6 (4), 6-2 win.
Rafael Nadal is in no hurry to join the trend of hiring big names. He is quite happy with uncle Toni and will not be seeking to appoint a former Grand Slam winner to his coaching team.
Top seed Novak Djokovic slipped and slid his way into the Wimbledon semi-finals on Wednesday, overcoming Marin Cilic and the distractions of Henman Hill to win 6-1, 3-6, 6-7(4), 6-2, 6-2 with the help of a new pair of shoes.
Three fancied players did succumb on a cheerless day.
A summary of Monday's action at the US Open.
A look at Roger Federer's worst five Grand Slam losses.
Victory meant Nadal set the record for the longest Davis Cup winning streak in combined singles and doubles rubbers with 23 matches in a row.
Eight-time Wimbledon champion Roger Federer, who turns 40 this year, takes on Frenchman Adrian Mannarino in round one.
Top-seeded world number ones Serena Williams and Novak Djokovic help launch the US Open tennis championships on Monday's opening day of the year's final Grand Slam.
Roger Federer cruised into the quarter-finals of the PNB Paribas Open at Indian Wells on Wednesday after Wimbledon champion Andy Murray and Australian Open winner Stanislas Wawrinka both fell in the fourth round.
Nick Kyrgios cranked down 42 aces as he opened his Wimbledon campaign with 7-6(3), 7-6(4), 6-7(5), 6-3 win over Uzbekistan's Denis Istomin on Tuesday.
Kei Nishikori exacted a measure of revenge against Marin Cilic when the Japanese world number five overcame the Croatian in the semi-finals of the Citi Open.
IMAGES from Day 6 of the matches played at the US Open at Flushing Meadows on Saturday.
Medvedev suffered a jarring early exit from the Canadian Masters last week but overcame some initial problems in a tricky tie against Shapovalov to edge both sets and book a meeting with American Fritz.
Australian Nick Kyrgios served like a demon to bounce Serbia's world number two Novak Djokovic out of the quarter-finals of the Acapulco International with a 7-6(9), 7-5 victory on Friday.
Maria Sharapova will face Serena Williams in the final of the Sony Open while Britain's Andy Murray will take on France's Richard Gasquet in the men's semi-finals after grinding down Croatian Marin Cilic.
Rediff.com brings you players who have tested positive for use of banned substances over the years.