Juan Martin del Potro
Juan Martin del Potro won the ATP 500 tournament in Acapulco on Sunday, March 4.PEDRO PARDO/AFP/Getty Images

Argentina tennis star Juan Martin del Potro believes he had the ability and firepower to challenge Roger Federer and Rafael Nadal during their heydays.

The 29-year-old though rued not being able to convert his potential into results in what has so far been an injury-ridden career.

Del Potro was considered tennis' "next big thing" when he won the US Open 2009 title. The Argentina hard-hitter took the sport by storm as he had crushed Rafael Nadal in straight sets in the semi-final before beating an in-form Roger Federer in a five-setter all at the age of 20.

However, del Potro was down with a wrist injury in the very next season and he even needed a surgery on his right wrist. The double-handed backhand player appeared to return to his best, winning titles in 2012 and 2013 before another wrist injury, this time on his left hand, forced him to sit out for nearly three years.

The former world no. 4 needed three surgeries to fix his left wrist before he returned to competitive action in 2016. Despite being able to hit booming serves and powerful forehand returns, Del Potro's backhand has been shaky ever since his latest comeback.

"I not only believed it [emulate Federer and Nadal] but I showed it on the court. Rafa [Nadal] never lost a Grand Slam semifinal [US Open 2009] with the result that I beat him. And Federer has not lost many Grand Slam finals with a guy other than Nadal or Djokovic," del Potro told Marca on the eve of Sunday's ATP 500 tournament win in Acapulco. 

"Technically I felt that I could fight against them but my career changed. Almost ten years after, I feel lucky for what I have," he added.

'Don't want Federer to retire'

Federer Nadal
File photo of Rafael Nadal and Roger Federer.MICHAL CIZEK/AFP/Getty Images

Del Potro started at the 1,041st spot on ATP rankings on his comeback in 2016. However, consistent performances have seen him make it to the top 10 once again.

The Argentine vaulted to the eighth spot following Sunday's win in Mexico. Del Potro made the best use of Nadal's withdrawal and crushed the likes of Dominic Thiem, Alexander Zverev, and Kevin Anderson to finish on the top step of the podium.

Meanwhile, Del Potro opined it is hard to imagine tennis without the likes of Federer and Nadal but conceded that the sport will soon have younger heroes. He added he doesn't regret playing in a competitive era, that saw the Big Four -- Federer, Nadal, Andy Murray and Novak Djokovic, dominate tennis for more than a decade.

"Yes, I want Roger to never retire and make this sport better and better. And the same thing I think about Rafa, Djokovic or Murray. Sometimes it is difficult to imagine tennis without them, without a Tsonga, without a Berdych, without my game. I don't even want to think about it," del Potro said.

"But time puts everyone in their place and tomorrow will come, new players, better players and I am privileged to have made my career with them and I would never complain that without them I would have had a better career or have won other things."