Tennis will never see a "big three" with the quality of Rafael Nadal, Novak Djokovic and Roger Federer again, believes Juan Martin del Potro.

The trio, who have combined for a total of 64 men's singles grand slam titles across a near-two-decade-long period of dominance, have come to define the sport's modern era.

Federer retired last year and while Nadal and Djokovic continue, both are well into the twilight of their careers, despite astonished continued success.

Del Potro, the 2009 US Open winner, also retired in 2022, and he thinks the trio's dominance is unlikely to be replicated going forward, even though he sees Carlos Alcaraz, Jannik Sinner and Holger Rune as three players who could possibly go on to enjoy great success.

"The only thing I lacked was being number one [in the ATP Rankings]," he said. "It was always a dream, and I always worked for it. I never made it because there was either Federer, or Nadal, or Djokovic.

"When I look at the rankings and the years of my career and who was fighting to be number one I see that it was beautiful that these were the ones who didn't let me make it, this dream."

"One day, the big three will end. We have Carlos Alcaraz, Jannik Sinner [and] Holger Rune, other young people who will mark the circuit.

"But for me, [for] many years, [it was] the big three. There will not be anything similar."

Del Potro reached a career high-mark of third in the ATP Rankings in 2018, with Andy Murray the only man other than Nadal, Federer or Djokovic to top the charts between 2005 and 2021.