World No 1 Alcaraz has made an astonishing start to his tennis career, with the 22-year-old having won six Grand Slam titles across the space of three years.
The Spaniard triumphed at the US Open in 2022 and 2025, the French Open in 2024 and 2025, and at Wimbledon in 2023 and 2024, with the chance to complete the Career Grand Slam at the Australian Open next January.
Should Alcaraz triumph at the Australian Open in 2026 or 2027, he would become the youngest man in the Open Era to have won all four majors, breaking the record set by Rafael Nadal at the 2010 US Open.
Alcaraz has been regularly compared to compatriot Nadal, a 22-time Grand Slam singles champion, across his career.
The older Spaniard, who retired at the end of 2024, was a contemporary of Williams, who herself holds an Open Era record of 23 Grand Slam women's singles titles.
US icon Williams is in Spain this week for the prestigious Princess of Asturias Awards, where she will receive recognition for her sporting achievements.
And, when asked about Spanish tennis during a press conference this week, she was quick to praise current star Alcaraz.
"Of course I know it (Spanish tennis) well - the Spanish have been at the top for a long time," said Williams. "There's Rafa (Nadal), of course, but there are many other wonderful tennis players.
"Alcaraz is doing incredible things. I'm a huge fan of Alcaraz. I always cheer him on."
With Alcaraz having already achieved so much in his career at such a young age, many have pondered if he could one day hold more Grand Slam titles than any other man.
That record is currently held by Djokovic, who has won a staggering 24 Grand Slam singles titles, narrowly ahead of Nadal on 22, and Roger Federer on 20.
The 'Big Three' are well ahead of any other men in tennis history, with Pete Sampras's haul of 14 Grand Slam singles titles ranking him in fourth.
Only Margaret Court (24) has won more Grand Slam women's singles titles in tennis history than Williams, who famously broke Steffi Graf's Open Era record of 22 majors at the 2017 Australian Open.
And, when asked about Alcaraz's chances of moving ahead of the 'Big Three', the American refused to discount the possibility.
She added: "When Federer started, no one thought he could surpass (Pete) Sampras, and he did.
"Then Rafa did the same, and then Djokovic. Carlos is very young, he has great rivals, but of course it's possible.
"Records are there to be broken."