Russian qualifier Daniil Medvedev stunned home favourite Kei Nishikori in Tokyo on Sunday, winning the final of the Japan Open 6-2, 6-4 in just over one hour.
"It's been an amazing year so far," said the 25-year-old Nishikori, who will move up to fourth from fifth in the world rankings. "I've had some good Grand Slams, too."
Fourth seed Kei Nishikori's hopes of making another magical U.S. Open run came to a quick end on Monday as last year's runner-up fell at the first hurdle, falling 6-4, 3-6, 4-6, 7-6 (6), 6-4 to Frenchman Benoit Paire.
World No 4 Del Potro is still sidelined with a right knee injury sustained in Shanghai last month.
Japan continued to maintain a keen interest in both singles tournaments at Wimbledon after Kei Nishikori advanced to the third round with a win over Ukrainian Sergiy Stakhovsky on Wednesday and Naomi Osaka followed suit in the women's draw.
Kei Nishikori was warned by tough taskmaster coach Michael Chang not to be satisfied, after having become the first Japanese man for almost a century to reach the US Open semi-finals, and to target the title.
Defending champion Novak Djokovic defeated Belgium's Steve Darcis 6-0, 7-5 on Monday to power into the last 16 of the Miami Open.
David Ferrer won a record-equalling fourth Mexican Open title with a 6-3, 7-5 victory over Kei Nishikori in the Acapulco hardcourt final.
Roger Federer's enduring brilliance and his sheer hatred of losing allowed him to withstand a stunning Kei Nishikori fightback and remain undefeated at the ATP World Tour Finals on Thursday.
World No 1 Novak Djokovic ended Kei Nishikori's impressive debut at the ATP World Tour Finals with a 6-1, 3-6, 6-0 semi-final victory at the O2 Arena on Saturday.
Local hero Kei Nishikori claimed his second Japan Open title on Sunday, overcoming familiar foe Milos Raonic 7-6(5), 4-6, 6-4 in the final under a closed roof at the Ariake Colosseum.
Jack Sock celebrated a pair of firsts on Friday by powering past fourth seed Kei Nishikori 6-3, 2-6, 6-2 to book a date with Roger Federer in the semi-finals of the BNP Paribas Open in Indian Wells, California.
Images from Day 8 of the 2021 French Open at Roland Garros in Paris on Sunday
Japan's Kei Nishikori will meet Spain's Feliciano Lopez in the final of the US National Indoor Tennis Championships after besting Australian Marinko Matosevic in the semi-finals in Memphis on Saturday.
His mere presence causes hysteria and pandemonium in the Land of the Rising Sun and he has no tennis equal in a continent heaving with 4.427 billion inhabitants, yet self-effacing Kei Nishikori thinks he is simply 'one' of the best players in Japan.
Swiss tennis maestro Roger Federer stepped up his bid for a record ninth Halle grasscourt title with a straight sets victory over Germany's Jan-Lennard Struff in the opening round on Wednesday.
Images from the matches played on Day 8at the Roland Garros on Sunday
Photos from the Miami Masters Sony Open played on Wednesday.
Zverev, who is looking for his fourth tournament win of the year, needed only 64 minutes to defeat Nishikori and move into the final in WashingtonDC where he will play Kevin Anderson after the South African beat Jack Sock by the same score.
Former world number one Novak Djokovic showed signs of a return to form with an impressive 7-5, 6-4 victory over Japan's Kei Nishikori in the opening round of the Madrid Open on Monday.
World number one Novak Djokovic survived a second set fightback from Slovak Martin Klizan before winning his opening match at the Miami Open 6-0, 5-7, 6-1.
Paire won his first ATP Tour title on the clay at Bastad in July and will go in search of his second against French Open champion Wawrinka, who served strongly in taking out Gilles Muller of Luxembourg.
India's World Group hopes are hanging by a slender thread as its top singles player, Somdev Devvarman is still doubtful to play Sunday's reverse singles in the play-off tie against Japan due to a shoulder injury.
Kei Nishikori reached his first Masters Series semi-final with a commanding 6-4, 6-3 victory over Ukraine's Alexandr Dolgopolov on Friday, underlining his imminent status as Japan's highest-ranked player ever on the ATP Tour. Awaiting the high-flying Asian star in the Shanghai Masters semi-finals is world number four Andy Murray, who comfortably ended Australian qualifier Matthew Ebden's dream run with a comfortable 6-3, 6-2 victory in the Qi Zhong Stadium.
Top seed James Blake eased into the US Clay Court Championships second round but fellow American Sam Querrey made an early exit.
Serena Williams and Ekaterina Makarova sprinted into the semi-finals of the U.S. Open on Wednesday but marathon man Kei Nishikori had to go the distance to upset Stan Wawrinka and become the first Japanese man into the last four of a grand slam in 81 years.
Defending champion Roger Federer became the second high-profile casualty at the Madrid Open when he was beaten 6-4, 1-6, 6-2 by Japanese 14th seed Kei Nishikori in the third round.
Japan's Kei Nishikori cut short Marin Cilic's title defence with an impressive 4-6, 7-6 (0), 6-2 win on Monday.
Images from Day 8 of the Australian Open in Melbourne on Monday.
Images from the matches played on Day 8 at the Australian Open at Melbourne Park on Tuesday
Defending champion Stan Wawrinka avoided a repeat on Wednesday of his first-round scare, though he was still made to work hard in a straight-sets win over Japan's Taro Daniel. The Swiss third seed won 7-6(7) 6-3 6-4 and is now on a six-match winning streak on clay, having warmed-up for Roland Garros by winning the title in Geneva last week. Progress was by no means straightforward against a skilful opponent ranked 93rd in the world and Wawrinka has yet to switch to his A game. But he says it's there when he needs it. "If you look at the first two matches, for sure I'm not playing my best tennis, but I know I have my best tennis in me," the 31-year-old Wawrinka, playing in his 45th consecutive grand slam tournament, told reporters.
Images from Day 1 of the Australian Open, in Melbourne, on Monday.
Kei Nishikori swept aside Rafael Nadal in the quarter-finals of the Rogers Cup.
Top seed Novak Djokovic overcame a strong challenge from Belgium's David Goffin to reach the Miami Open final with a 7-6(5), 6-4 victory on Friday as he continued his pursuit of a fifth title in six years on Key Biscayne.
Bulgaria's Grigor Dimitrov upset top seed and defending champion Milos Raonic of Canada at the Brisbane International on Saturday to set up a title clash against Japan's Kei Nishikori.
A summary of sports events and persons who made news on Friday
Roger Federer was made to work hard by Fernando Verdasco before beating the Spanish veteran 6-3, 3-6, 6-3 on Wednesday to reach the quarter-finals of the Dubai Duty Free Tennis Championships.
Bernard Tomic is set to sit out the Australian Open after Tennis Australia (TA) decided not to award him a wildcard to the main draw, the organisers said on Thursday.
World No.1 Serena Williams has refuted any hints of match-fixing in women's tennis. World tennis was rocked on Monday by allegations that 16 players who have been ranked in the top 50 had been repeatedly flagged to the Tennis Integrity Unit (TIU) over suspicions they had 'fixed matches' in the past decade. The media reports created a stir at the Australian Open, with players expressing surprise at the allegations. "When I'm playing, I can only answer for me, I play very hard, and every player I play seems to play hard," women's world number one Serena Williams told reporters.
With the Australian Open currently on, defending champion Novak Djokovic has once again been dubbed as a favourite to retain the title, and former world No. 17 Bernard Tomic of Australia firmly believes there will be no one to challenge the great Serbian.