Robin Haase opens up on loss to Roger Federer and explains how Rafael Nadal can curb Swiss ace's progress

Robin Haase has reflected on his performance against Roger Federer in the Rotterdam Open, stating that he had been sick the whole week and did not come into the game at 100%. The Dutchman lost to Federer in a three-set quarter-final match, being the only player at the event to win a set against the Swiss ace.

Federer eventually went on to win the tournament and also made his way to become the world number one again for the first time since 2012, his fourth stint at the top of the charts in his career. He became the oldest player ever to achieve the feat as well, beating Andre Agassi, who topped the rankings when he was 33 years old in 2003.

Federer's achievement came days after he won the Australian Open in Melbourne — his 20th Grand Slam title in his journey to the top. The 36-year-old has now won three of the last five majors and victory in Melbourne was his sixth Australian Open championship win in what has been an illustrious career.

He became only the fourth player after Margaret Court, Serena Williams and Steffi Graf to win 20 or more major singles titles.

Haase, who fell on the wrong end of yet another Federer masterclass, believes that the Swiss ace can continue doing what he has over the years for many more years but will face competition from Rafael Nadal if the Spaniard can stay fit.

"Obviously, I was disappointed that I lost, but how disappointed can you be? I had been sick the whole week, was kind of a little injured, and you play Roger Federer," Haase said, as quoted by Tennis World USA.

"If I had been 100%, I was probably not going to win. So considering all these things, I think I can be proud to win the first set, giving it all my best, even though in the second and third set, I was empty and just not good enough anymore.

"He's getting older. How many tournaments can he play and how are the other guys going to play? If Nadal is going to play as many tournaments as he can and stays fit, it's going to be difficult for Roger to keep winning all the tournaments, because he just plays a few and kind of has to win them all to stay number one."