At the age of 19 years and 214 days, US Open champion Alcaraz surpasses Lleyton Hewitt’s record of ending the year as world No. 1 aged 20 years and 275 days in 2001.
Alcaraz is missing this year’s ATP Finals in Turin, Italy as he continues his recovery from an abdominal injury sustained at the Paris Masters earlier this month, but compatriot Nadal’s early exit from the tournament means he still has cause to celebrate.
The teenager has enjoyed a sensational year, winning five ATP titles and becoming the youngest No. 1 in men’s tennis when he won his first grand slam title in New York.
Nadal could have leapfrogged Alcaraz at the top of the world rankings with victory in Turin this week, but after he lost 6-3 6-4 against Felix Auger-Aliassime on Tuesday and Casper Ruud won a set against Taylor Fritz, the 36-year-old bowed out of the tournament.
Nadal has struggled for form since the US Open in September and against Auger-Aliassime fell to his fourth consecutive feat since 2009.
It follows a straight-sets loss to Taylor Fritz in Turin earlier this week and defeats against Tommy Paul at the Paris Masters and Frances Tiafoe at the US Open.
“I don’t think I forgot how to play tennis, how to be strong enough mentally,” Nadal told reporters on Tuesday.
“I just need to recover all these positive feelings and all this confidence and all this strong mentality that I need to be at the level that I want to be.
“I don’t know if I’m going to reach that level again. But what I don’t have any doubt [about] is that I [am] going to die for it.”
Nadal had chances to take the lead against Auger-Aliassime, but failed to convert four break points in the first set. The Canadian moved 5-3 ahead when he broke Nadal’s serve and wrapped up the set shortly after for an early lead.
In the second set, Auger-Aliassime broke Nadal at 1-1, then consolidated his advantage the following game with three aces in a row.
The world No. 6 hit 15 aces throughout the match and proceeded to serve out for the win in close to two hours.
It means Auger-Aliassime stays in contention to progress beyond the groups stages at the ATP Finals despite losing to Ruud in his opening match on Sunday.