Andrey Rublev reached the final of the Qatar Open on Friday with a 7-5, 4-6, 7-6(5) win over Canada's Felix Auger-Aliassime, and will meet Jack Draper in the decider after the Briton beat Czech Jiri Lehecka.
Rublev dug deep in the third set and was a break ahead but Fonseca showed incredible poise and maturity at critical moments to set up another tiebreaker.
Djokovic has declined to disclose whether he is vaccinated, citing privacy.
Greece's Tsitsipas battled back from 3-5 down in the third set to eliminate Medvedev with a 6-3, 6-7(11), 7-6(1) win to set up a showdown on Friday with Rublev for the Red Group's other semi-final spot.
Philippine wildcard Alexandra Eala pulled off the biggest win of her young career with a stunning upset of Polish world number two Iga Swiatek.
An off-colour Alcaraz lost 6-1, 7-5 to Norway's Casper Ruud in his opening match on Monday and the 21-year-old cancelled a public training session the following day.
Jannik Sinner overpowered American Taylor Fritz in the final to become the first Italian man to win the US Open singles title.
But Ruud, a semi-finalist last year, stamped his authority in the tiebreak and did not face a single break point in the match as he beat the Canadian for the second time this year.
Sumit Nagal on Monday dropped out of the much-desired bracket following a string of poor show
Casper Ruud has become the first Norwegian to book a place in the season-ending ATP Finals, leaving one spot to be filled at the tournament in Turin, Italy later this month.
Alexander Zverev into ATP Finals semis after straight sets win over Carlos Alcaraz
Dimitrov was showing signs of fatigue from his three-hour third-round match earlier in the week and could do little to stop the Spanish world number three, who next faces Argentine Francisco Cerundolo.
No. 2 seed Casper Ruud of Norway will take on unseeded Denis Shapovalov of Canada in the Dallas Open final on Sunday after both notched semi-final victories.
Rohan Bopanna and Nicolas Barrientos bowed out of the Australian Open men's doubles with an opening-round loss to the Spanish team of Pedro Martinez and Jaume Munar.
Russian Andrey Rublev has become the fifth singles player to qualify for the season-ending ATP Finals in Turin next month, the men's tour said.
Novak Djokovic said a majority of players believe favouritism is at play in the tennis anti-doping system.
Former champion Naomi Osaka was sent packing from Indian Wells after losing in straight sets to Colombia's Camila Osorio.
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.
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.
Novak Djokovic is ready to challenge Jannik Sinner and Carlos Alcaraz at the Grand Slam stage when he returns to action at the Australian Open after an underwhelming campaign this year, the 24-times champion said.
Alexander Zverev cruised past Frenchman Lucas Pouille in straight sets in the first round of the Australian Open on Sunday.
The events will be on single-year licence as the ATP offers professionals the opportunity to earn money and ranking points in the wake of the coronavirus shutdown.
AITA President Anil Jain, who was accused of using his position for personal gains, avoided facing a no-confidence motion from the state associations only after he agreed to step aside.
Novak Djokovic dug out a 6-7(4) 6-1 6-4 win over Czech Jakub Mensik on Friday to advance to the semi-finals of the Shanghai Masters, where he will face Taylor Fritz.
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.
Novak Djokovic's bid to add a 100th singles title to his trophy cabinet on Sunday was dashed after he was beaten 7-6(4), 6-3 by world number one Jannik Sinner in the Shanghai Masters final on Sunday.
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.
Prajnesh Gunneswaran announces retirement from professional tennis
The Serbian Wimbledon champion extended his win streak to nine, wrapping up the final in 75 minutes without facing a break point and booked his place at next month's ATP Finals.
Novak Djokovic beat Norway's Casper Ruud 7-5, 6-3 to collect a record-equalling sixth ATP Finals title on Sunday, earning the biggest paycheck ever in tennis - $4,740,300 - for completing the season-ending tournament unbeaten.
'I think he's bringing a fresh look to my game and I'll be able to benefit from that, no doubt, on the court. But also that champion mentality he has, I'm sure we'll match very well.'
Tommy Paul led a parade of seeded players into the quarterfinals on Wednesday at the Adelaide International in Australia.
Sumit Nagal attains career-high ATP ranking of 68
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.
Learner Tien is the youngest American man to reach the third round of the Australian Open since an 18-year-old Pete Sampras in 1990.
The Indian jumped six places following his runner-up finish at the Perugia ATP Challenger tournament on Sunday.
-French flair topped American firepower as Gael Monfils turned back the clock to dump fourth seed Taylor Fritz out of the Australian Open on Saturday and celebrate his place in the last 16 with a dance on court.
Djokovic was soundly beaten by Zverev in the 2018 final, a match played out in an electrifying atmosphere in front of 18,000 fans. This time the arena was empty because of the COVID-19 lockdown, a surreal backdrop for a match with so much riding on it for both men.
Novak Djokovic's bid for a 100th ATP Tour title gained momentum on Thursday
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.
