Andy Murray put down an early warning for the Davis Cup final when he dismantled David Goffin 6-1, 6-0 in awe-inspiring fashion to reach the quarter-finals of the Paris Masters on Thursday.
World No 1 Novak Djokovic had no explanation for his flat performance in a stunning semi-final loss to Japan's Kei Nishikori at the U.S. Open on Saturday.
Eighteen time Grand Slam champion Roger Federer has climbed up to the fourth spot in the latest ATP rankings after lifting his third Miami Open title by beating long-time rival Rafael Nadal.
Nadal no longer 'immovable' object in Paris.
A break-out 2014 season and a career-high ranking of five has added extra weight to Kei Nishikori's shoulders, with the US Open finalist already bearing the burden of huge expectations in his home country Japan.
Japan's Kei Nishikori made a stunning start to what will surely be the first of many appearances at the ATP World Tour Finals with a 6-4, 6-4 win over home favourite Andy Murray on Sunday.
Nadal thrashes Nishikori; Federer downs Wawrinka
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.
It was his first victory ever against a player ranked in the top two and it avenged the semi-final loss at the Rio Olympics where Murray went on to win gold and Nishikori settled for bronze.
The fifth seed's success made it the first time a Japanese male player had reached the last eight at Roland Garros since Jiro Satoh made it to the semi-finals in 1931 and 1933.
Champion Novak Djokovic did not bother with a practice hit before his showdown with Kei Nishikori and his "less is more" approach paid off with an easy 6-3, 6-2, 6-4 win on Tuesday to set up a blockbuster Australian Open semi-final with Roger Federer.
The eight seeded South African fought back after losing the first two sets to defeat the Swiss ace 2-6, 6-7(5), 7-5, 6-4, 13-11.
Some players and pundits have criticised the rule as being hard to police, spottily enforced and highly subjective, and called for the ban on coaching from the players' box to be lifted.
Images from Day 6 of the 2021 US Open in New York on Saturday.
Rafael Nadal's decision to end his season early means Cilic is actually holding the last berth for the eight-man showdown at London's O2 Arena.
The former world number four, looking for a first Grand Slam title having been US Open runner-up in 2014, blasted Kyrgios off court as he raced through the first set in 16 minutes.
Stan Wawrinka outslugged Japanese sixth seed Kei Nishikori 4-6, 7-5, 6-4, 6-2 in energy-sapping humidity at Flushing Meadows on Friday to set up a US Open final against world number one Novak Djokovic.
Japan's Kei Nishikori surged to a three-set victory over alternate David Ferrer at the ATP World Tour Finals on Thursday before sitting back to watch his fate unfold in the night match.
Novak Djokovic felt he was a different player to the Wimbledon winner of old but comparisons were inevitable on Wednesday as the Serb rolled into the semi-finals for the first time since 2015.
Top seed Kei Nishikori of Japan became the first player to win three consecutive Memphis Open tennis tournament titles when he prevailed in straight sets on Sunday.
A pioneering Kei Nishikori blazed a new trail for Japanese tennis with a shock win over World No 1 Novak Djokovic at the U.S. Open on Saturday, becoming the first man from Asia to book a place in a Grand Slam final.
Czech Tomas Berdych booked his place in the ATP World Tour Finals for the fifth time in a row when he advanced into the semi-finals of the Paris Masters with a 6-7(4) 6-4 6-4 victory over South African Kevin Anderson on Friday.
18-year-old Carlos Alcaraz earned his first ATP Masters 1000 crown
There comes a moment in all great sporting careers when the puzzle fits together and for Kei Nishikori it arrived on a sweltering early September afternoon in New York.
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.
The Italian is the youngest winner on the men's tour since Japan's Kei Nishikori won the Delray Beach Open at the age of 18 in 2008.
World No 1 Rafael Nadal will play local hope Bernard Tomic in the first round of the Australian Open as he bids for a 14th Grand Slam title.
Marathon man Kei Nishikori secured a monumental upset by sweating out a 6-4, 1-6, 7-6(4), 6-3 win over world number one Novak Djokovic at the U.S. Open on Saturday to become the first Japanese man to reach a Grand Slam final.
Top seed Kei Nishikori is on track for a three-peat at the Memphis Open after a narrow semi-final victory on Saturday.
Grit, determination, nerves were all on show at the US Open final.
Novak Djokovic eased into the last four with a commanding performance over Japan's Kei Nishikori but world number two Daniil Medvedev bowed out of the men's singles at the Tokyo Olympics.
Japan's Kei Nishikori and Victoria Azarenka of Belarus continued their Australian Open preparations by swiftly marching through to the quarter finals of the Brisbane International on Wednesday.
Marin Cilic hit all the right notes in a dominant 6-3, 6-3, 6-3 win over Kei Nishikori in the US Open final on Monday but it remains to be seen if the big Croatian is another one Slam wonder or perennial threat.
News of all that's transpired on and off the tennis courts
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.
Rafael Nadal reached the final of the Barcelona Open for the ninth time by beating German Philipp Kohlschreiber 6-3, 6-3 on Saturday.
The 6-2, 2-6, 6-3 win at the Pat Rafter arena was the 25-year-old's first in four attempts against world number five Nishikori and will boost his confidence ahead of the Australian Open, which starts on January 16 in Melbourne.
Japan's Kei Nishikori overcame Daniil Medvedev in the Brisbane International final on Sunday for his first ATP title in nearly three years and the 12th of his career.
Rafael Nadal set up an Italian Open semi-final with Stefanos Tsitsipas on Friday thanks to a 6-4, 6-0 win over Fernando Verdasco.
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.
