Australian Open holder Djokovic will make his ATP Cup debut for Serbia against South Africa in Brisbane on Saturday while Nadal will lead Spain into action against Georgia in Perth on the same day.
Top-ranked Iga Swiatek of Poland faces Irina-Camella Begu of Romania in the opening round of the women's draw with second-seeded American Coco Gauff taking on Australian Ajla Tomljanovic.
Ace Indian tennis player Sumit Nagal was off to a winning start in Monte Carlo Masters as he defeated world number 63 Flavio Cobolli of Italy in straight sets in the qualifiers in Monte Carlo on Saturday.
Australia's Nick Kyrgios could find himself in hot water again after accusing men's tennis governing body ATP of being "corrupt" following his US Open first round victory.
Nishikori is the latest high-profile men's player to pull out of the season's first Grand Slam following the withdrawal of Briton Andy Murray on Saturday.
The winners of the Serbia-Germany tie will join Spain, Russia and Italy in the semi-finals.
Nagal is coming off a title triumph during the Heilbronn Challenger last week, which happens to be his second Challenger title this season after the Chennai Challenger in February.
World No. 72 Nagal has a tough road ahead as he is placed in the same section of the draw as top seed and World No. 1 Jannik Sinner
The Serb set up the breakaway PTPA on the eve of the US Open in September and resigned as head of the player council but last month he confirmed that he had been nominated by his fellow professionals for the current elections which he accepted.
The ATP tour, which was suspended in March due to the novel coronavirus outbreak, is set restart on Aug. 14 with the Citi Open, followed by the Cincinnati Masters, which will be held at Flushing Meadows before the US Open.
Twenty four time Grand Slam champion Novak Djokovic closed the 2023 ATP season by clinching the year-end No. 1 spot for a record-extending eighth time.
French Open and Wimbledon champion Alcaraz, who won both of his previous meetings with Sinner this year, recovered from a slow start to wrap up victory in three hours, 21 minutes and improve his head-to-head record with the Italian to 6-4.
Federer was joined by his wife Mirka, who herself made a pretty picture in a black collared gown.
India's non-playing Davis Cup captain Rohit Rajpal on Saturday clarified that his "shut-up" remark was meant for a few "agenda-driven" people consistently targeting him and was not directed at the country's tennis community as has been projected.
Djokovic etched his name in history by clinching a record 24 Grand Slam titles
The hosts had blanked Germany in their opening tie and became the first to seal a quarter-final spot with their second 3-0 win in the inaugural team event.
Yuki Bhambri and his Dutch partner Robin Hasse went down in straight sets to Ivan Dodig and Austin Krajicek at the Dubai Duty Free Tennis Championships.
The 32-year-old debutant at the ATP's blue riband event won the first 11 games of the round-robin clash before a relieved Nishikori finally got on the scoreboard with an angled winner.
Nadal was much more than a claycourt bully, though. He spent more than 900 successive weeks from 2005 in the ATP's top 10, 209 of them at number one and at the age of 24 became the youngest player to complete the career Grand Slam.
The Bangalore Open scheduled to be held from September 29 has been suspended due to the local promoter's security concerns, according to the Association of Tennis Professionals (ATP) Board.
Sumit Nagal, who recently became the first Indian to beat a seeded player in a Grand Slam tournament, will spearhead the Indian challenge in the men's singles competition of the Chennai Open ATP Challenger 100 tournament beginning on Sunday.
Fresh from his exploits in India's first-ever title-winning campaign at the Chess Olympiad, Grandmaster Vidit Gujrathi has decided against defending his crown at the 10th Vugar Gashimov Memorial Chess Super Tournament in Azerbaijan for an audience with Prime Minister Narendra Modi here on Wednesday.
Australian top seed Alex de Minaur moved into his second consecutive final at the Next Gen ATP Finals with a 4-2, 4-1, 0-4, 4-2 victory over Frances Tiafoe in Milan on Friday.
Rafa Nadal suffered a setback in his Paris 2024 Olympics preparations on Sunday as he was beaten 6-3 6-2 in the Swedish Open final by Portuguese seventh seed Nuno Borges.
Jannik Sinner is primed for a Wimbledon title tilt after picking up his first grasscourt trophy at Halle
The Railway Board has reduced the speed of semi-high speed trains Gatimaan Express and Vande Bharat from 160 kmph to 130 kmph till the automatic train protection system gets operational.
India's first and only tennis medal in the history of Olympic Games came way back in 1996, when Leander Paes claimed the singles bronze in Atlanta.
Rafael Nadal teamed up with Norwegian Casper Ruud to register a 6-1, 6-4 win over second seeds Guido Andreozzi and Miguel Reyes-Varela on the Swedish clay.
Laura Siegemund entered the record books with her defeat of fifth-seeded Xiyu Wang of China in four hours, nine minutes at the Thailand Open in Hua Hin on Wednesday.
Italian Bracciali banned for life, Starace for 10 years
Sumit Nagal got the big break as he was the highest ranked player in that draw.
Muguruza wins all-Spanish clash with Badosa at WTA Finals
Alexander Zverev has agreed a settlement after the mother of his child accused him of physical abuse and a German court closed the case on Friday, the French Open semi-finalist's lawyers said
Chilean 21st seed Nicolas Jarry outclassed American Tommy Paul 6-3, 6-7(3), 6-3 to reach the Italian Open on Friday as former champion Alexander Zverev recovered from a slow start to beat Chilean Alejandro Tabilo 1-6, 7-6(4), 6-2.
It was Sumit's second Challenger title of his career
Yuki Bhambri made his first doubles semi-finals of the ATP 500 tour.
Daniil Medvedev fired Russia into the final of the ATP Cup on Saturday with a tense 3-6, 6-3, 7-5 win over an injury-hampered Alexander Zverev after the German destroyed a racket in frustration over a lost service break.
American great Billie Jean King had called for a unified governing body for men and women years ago but the 29-year-old Johanna Konta feels Federer's comments have brought attention back to the topic.
World number one Novak Djokovic began his quest for a sixth title at the season-ending ATP Finals with a 7-6(4), 6-2 victory over Norway's Casper Ruud in their round robin encounter in Turin on Monday.