Davis Cup heavyweights Australia and the United States eased through the first qualifying round on Saturday but Britain were knocked out as Japan hit back from 2-1 down to win 3-2, while Denmark staged a dramatic comeback to overcome Serbia.
Djokovic saved three breakpoints in stifling conditions to go 5-4 up but lost the opening set in a tough tiebreak as Opelka cranked up his serve
The former world number one, who is easing his way back to full match fitness after a career-saving resurfacing procedure in January, saved all four break points he faced and dropped only six points on his first serve.
Daniil Medvedev destroyed his racket and a net camera in a mid-match meltdown as he survived a huge scare against Thai wildcard Kasidit Samrej.
The Swiss star underwent arthroscopic right knee surgeries in February 2020 and May 2020. Federer has played five tournaments since having those surgeries, all of which came this season.
The Croatian helped Djokovic claim nine of his 24 Grand Slam titles before leaving his team in March and on Friday was hired to coach world number five Rybakina for the 2025 season.
Retired tennis great Andy Murray has agreed to join Novak Djokovic's team and will coach him at the Australian Open next year, the Serbian 24-times Grand Slam champion said on Saturday.
Novak Djokovic has pulled out of the Serbia team for the ATP Cup in Sydney, event organisers said on Wednesday, raising further doubts over whether the world number one will defend his Australian Open title next month.
While Daniil Medvedev remained the world number one, 2022 Wimbledon champion Novak Djokovic dropped to seventh position after the grass-court Grand Slam tournament was stripped of ranking points for banning Russian and Belarusian players.
Britain's Andy Murray joined world number one Novak Djokovic and newly-crowned US Open champion Rafa Nadal as definite qualifiers for the ATP World Tour finals on Tuesday, but Roger Federer faces an uphill task to make the eight-man field.
Frances Tiafoe launched into a foul-mouthed tirade directed at a chair umpire after the American received a time violation and then lost to Roman Safiullin in the third round of the Shanghai Masters on Tuesday.
Third seed Alexander Zverev eased past home favourite Ugo Humbert
The last time the Swiss maestro was this far down in the ATP rankings was all the way back on January 2001, when Federer was just 19 years old. Notably, he was yet to win his first tour title.
Rohan Bopanna's and Aisam-ul-Haq Qureshi's wait for their first ATP title continued after they lost the final of the Pilot Pen Tennis tournament to Wimbledon finalists Robert Lindstedt and Horia Tecau in New Haven, USA.
Jack Sock ended local favourite Julien Benneteau's run at the Paris Masters with a 7-5, 6-2 victory to reach the final and move to the brink of an ATP Finals spot on Saturday.
Italian Bracciali banned for life, Starace for 10 years
The seventh seed Indian overcame stiff resistance from American Daniel Nguyen before prevailing 7-5, 4-6, 7-6(5) in the rain-hit final that lasted three hours and 31 minutes, turning out to be the longest summit clash in the ATP Challenger Tour history.
American qualifier Steve Johnson is through to his first ATP Tour semi-final after an emphatic victory at the Delray Beach Open on Friday.
While several top seeds will have their say, a look at some emerging players who could be serious contenders.
Sasikumar Mukund will aim for a winning return to the Davis Cup fold as India faces Togo in the World Group I Play-off.
Sumit Nagal staged a grand recovery to get the better of Jason Jung of Chinese Taipei 3-6, 6-2, 6-0 and book his place in the quarter-finals of the Chennai Open ATP Challenger in Chennai on Thursday.
Russian Daniil Medvedev's 2022 season opened with a stunning defeat at the hands of Frenchman Ugo Humbert after a three-hour dogfight in a steamy Ken Rosewall Arena at the ATP Cup on Sunday.
The Indo-Pakistan tennis duo of Rohan Bopanna and Aisam-ul-Haq Qureshi has booked a berth in the season-ending ATP World Tour Finals to be held from November 20 to 27 at London's O2 arena.
Both scored contrasting semi-final victories on Saturday.
World number one Novak Djokovic will bid for a record fourth successive ATP World Tour Finals crown in London later this year after becoming the first man to qualify for the season-ender.
Russia's Andrey Rublev overcame Grigor Dimitrov 7-6(7), 6-3 in their semi-final clash at the Shanghai Masters on Saturday, and will now face Hubert Hurkacz, who beat Sebastian Korda.
World No 1 Rafael Nadal is confident that arch-rival Roger Federer will be able to accumulate the points needed over the next few weeks to seal his spot for the season-ending ATP finale in London.
Jannik Sinner secured the year-end world number one ranking by beating Czech 30th seed Tomas Machac in the Shanghai Masters semi-finals.
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.
The Indian has won five ATP Masters 1000 titles with five different partners, although he has never won a major championship in men's doubles. Not bad for someone whose knees lack cartilage.
Djokovic looked in fine nick in Shanghai, playing with consistency throughout the tournament to reach his fifth final at the ATP Masters 1000 event
Casper Ruud gained sweet revenge over Stefanos Tsitsipas as he beat the Greek fifth seed 7-5, 6-3 to win the Barcelona Open on Sunday.
Roger Federer's decision to withdraw means Switzerland can no longer take part in the nation-based event on January 3-12
Alcaraz will hope to bury memories of an injury-plagued start to last year when he missed the Australian Open
The unanswerable question, of course, is whether Djokovic is the GOAT. That's a complex issue over which fans will forever bicker, observes Kanika Datta.
French Open champion Stan Wawrinka has become the fourth player to qualify for the season-ending ATP World Tour Finals in London.
After registering a runner-up finish in the Qatar Open, Andy Murray set himself a target of registering 800 career wins.
One thing is beyond doubt after eight fabulous days of action at the ATP World Tour Finals -- tennis has found a spectacular new venue at London's space-age O2 Arena.
The Spaniard bore little resemblance to the player who once terrorised his opponents as he slumped to a 6-1, 7-6 defeat by Russia's Nikolay Davydenko.
Home favourite Kei Nishikori defeated Frenchman Richard Gasquet 7-6(2), 6-1 in the semi-finals of the Japan Open on Saturday, setting up a final against Russian qualifier Daniil Medvedev.