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.
Alexander Zverev into ATP Finals semis after straight sets win over Carlos Alcaraz
Madison Keys was dumped out of the Miami Open third round on Sunday, falling 6-4, 6-2 to Philippine wild card Alexandra Eala
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.
Roger Federer's decision to withdraw means Switzerland can no longer take part in the nation-based event on January 3-12
Friction has dogged the ATP Player Council, whose president is world number one Novak Djokovic, this year since ATP president Chris Kermode failed to gain support for another term.
Tommy Paul led a parade of seeded players into the quarterfinals on Wednesday at the Adelaide International in Australia.
Sumit Nagal on Monday dropped out of the much-desired bracket following a string of poor show
Organisers played a wrong national anthem for Moldova ahead of their tie against Belgium in Sydney. Denis Shapovalov won the battle of the next generation against Greek Stefanos Tsitsipas to help Canada to an emphatic 3-0 victory in the inaugural ATP Cup men's team event in Brisbane on Friday.
World number one Novak Djokovic, bidding for a record-equalling sixth title at the event, is in the Tokyo group with Russian Daniil Medvedev, Germany's Alexander Zverev and Argentine first-time Diego Schwartzman.
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.
Philippine wildcard Alexandra Eala pulled off the biggest win of her young career with a stunning upset of Polish world number two Iga Swiatek.
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.
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.
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.
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.
Novak Djokovic is bidding to win the title for the first time since 2015 and equal Roger Federer's six.
Novak Djokovic said a majority of players believe favouritism is at play in the tennis anti-doping system.
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.
Sumit Nagal attains career-high ATP ranking of 68
The ATP Finals, in its 50th edition, is being staged in London's O2 Arena for the 12th and last time before it moves to Turin and sadly plans for a vibrant farewell party in front of the usual sell-out crowds has been scuppered by the COVID-19 pandemic.
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.
Alexander Zverev cruised past Frenchman Lucas Pouille in straight sets in the first round of the Australian Open on Sunday.
The Indian jumped six places following his runner-up finish at the Perugia ATP Challenger tournament on Sunday.
Germany's Alexander Zverev beat Russian world number two and defending champion Daniil Medvedev 6-4, 6-4 in the summit clash of the ATP Finals on Sunday to win the title for the second time in his career.
Former champion Naomi Osaka was sent packing from Indian Wells after losing in straight sets to Colombia's Camila Osorio.
With world number four Ruud already assured of a semi-final berth the match was in reality a dead rubber.
Prajnesh Gunneswaran announces retirement from professional tennis
Paire, ranked 29 in the world, said the sport had become a 'tasteless job'.
'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.'
Even though he withdrew from his semi-final tie with Denis Shapovalov, Nadal's run to the last four in Paris saw him reclaim the number one spot from Novak Djokovic on Monday.
Rafael Nadal and Novak Djokovic won their matches for their respective countries on Day 4 of the ATP Cup on Monday.
World number one Novak Djokovic had enough on his plate already on Wednesday without marauding Russian Daniil Medvedev pummelling him to a shock 6-3, 6-3 defeat at the ATP Finals.
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.
Novak Djokovic, who has won a record nine titles at Melbourne Park including the last three, has repeatedly declined to reveal whether he has been vaccinated against COVID-19, with Australian Open organisers Tennis Australia confirming that all players would have to be vaccinated to compete in Melbourne.
India's singles challenge has already ended with both Sumit Nagal and Ramkumar Ramanathan making first round exits.
-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.
Novak Djokovic's bid for a 100th ATP Tour title gained momentum on Thursday
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.
Factbox on Carlos Alcaraz, who beat Alexander Zverev
