Italy's Sinner and Spain's Alcaraz have won two Grand Slams each this year, with Alcaraz beating Sinner in closely fought clashes at the French Open semi-finals and the China Open final.
Mats Wilander said it was a 'miracle' that Nadal won two majors during the year.
Sitting courtside, Rafael Nadal cried as his great rival, Roger Federer, bid an emotional farewell to tennis at the Laver Cup on Friday, later saying an important part of him was also leaving the men's Tour with the retirement of the Swiss.
World number two Rafael Nadal will be sidelined for six to eight weeks by the hip flexor injury he suffered during his second-round loss at the Australian Open, the Spaniard's team said on Thursday.
'This probably hurts more than any loss I've ever had'
Like a stern headmaster, a clearly irritated Rafael Nadal beckoned Lorenzo Sonego to the net and gave him an earful about the etiquette of tennis in front of 15,000 wide-eyed fans and a global audience of millions.
Auger-Aliassime, now coached by Nadal's uncle and long-time mentor Toni who sat in his box, will face Fritz in his final group match with a chance of making the last four.
Jannik Sinner spearheaded Italy's charge towards a second successive Davis Cup title with a 2-0 victory over the Netherlands in the final at the southern Spanish city of Malaga on Sunday.
Rafael Nadal said on Friday that he intends to compete at Wimbledon later this month
Rafael Nadal dug deep to beat mercurial wildcard Nick Kyrgios 7-6(0), 5-7, 6-4 in a blockbuster quarter-final match that lived up to the hype at Indian Wells on Thursday.
Carlos Alcaraz beat Novak Djokovic in the Wimbledon final to win his fourth Grand Slam title.
Sinner, Alcaraz will keep tennis' flag flying: Shastri
On Sunday, Rafael Nadal's extraordinary resilience was on full display as he closed out a marathon five-setter against World No 2 Daniil Medvedev.
It was a case of more pain than gain for Nadal since he hoisted the Musketeers' Cup for a record 14th time in June.
'Rafael Nadal withdrew for personal reasons'
The world number five Spaniard has won 15 straight matches since returning from a foot issue that sidelined him for nearly six months last year.
Nadal confirmed the rumours that he will be a father soon.
Novak Djokovic reclaimed the world number one ranking from Carlos Alcaraz
The 35-year-old said that the presence of his personal doctor to "do things that help" made sure he could play in Paris although he is unsure of what will come next.
Singles wins for Botic Van de Zandschulp and Tallon Griekspoor sparked a party amongst an army of orange-clad Dutch fans inside the Jose Maria Martin Carpena arena.
Some of the most iconic moments of Roger Federer's glittering career featured Rafael Nadal across the net but on Friday his great Spanish rival will be alongside him for his final bow.
Their epic rivalry includes three successive Wimbledon finals from 2006
Australian Open champion Rafael Nadal resumed training on Monday after four weeks out due a stress fracture in his rib, a month out from the French Open where the Spaniard will bid for a record-extending 14th title.
Defending champion Rafa Nadal began his Italian Open campaign with an emphatic 6-3 6-1 victory over big-serving American John Isner to move into the last-16 on Wednesday.
Rafael Nadal called Novak Djokovic's COVID-19 vaccination controversy in Australia "a circus" and joked that he would prefer that the world number one tennis player didn't play at the upcoming Australian Open.
Rafael Nadal returns to the US Open for the first time in three years short of match practice and with big question marks about his fitness but few people will dismiss the Spaniard's chances of claiming a record-extending 23rd Grand Slam title.
Zverev will have a chance to spoil the birthday party for Nadal, who turns 36 on Friday
Rafael Nadal said he would love to keep playing long enough for his son to remember him on court, though the 22-time Grand Slam champion concedes time is not on his side.
World number one Carlos Alcaraz sailed into the Paris Masters third round with a 6-4, 6-4 win over Yoshihito Nishioka but Rafael Nadal and Daniil Medvedev both slumped to surprise losses on Wednesday.
Rafael Nadal's hopes of completing a rare calendar year Grand Slam ended on Thursday when the Spaniard pulled out of his highly-anticipated Wimbledon semi-final showdown against Australian Nick Kyrgios with an abdominal strain.
Second seed Rafael Nadal said he would make no excuses after his shock loss to American Frances Tiafoe in the US Open fourth round Monday, despite a serious abdominal injury that derailed his run-up to the year's final major.
Nadal had said last week that daily training was a challenge and he would take a doctor with him to Paris
Despite all the trials and tribulations he suffered in the build-up, no one could prevent Nadal from lifting the Musketeers' Cup for a record-extending 14th time.
Novak Djokovic said the pursuit of Olympic gold left him without much in the tank for his US Open title defence.
Nadal had said that he did not know if he would be fit to play against Australian Kyrgios, after appearing close to retiring mid-match against Fritz on Centre Court.
Djokovic looked in fine nick in Shanghai, playing with consistency throughout the tournament to reach his fifth final at the ATP Masters 1000 event
Rafa Nadal returned from an injury layoff to beat Miomir Kecmanovic 6-1 7-6(4) on Wednesday
Yet the warrior-like instincts kicked in and we were all reminded that Nadal, as long as he is standing, remains a physical and psychological force of nature on a tennis court.
Rafael Nadal will become the first man to win 21 Grand Slam titles if he defeats the Russian in Melbourne.
With world number four Ruud already assured of a semi-final berth the match was in reality a dead rubber.