World No. 1 Rafael Nadal issues a warning to other quarter-finalists of the Australian Open when he asserted that his game with nemesis Croatian Marin Cilic is his best match since the beginning of this year's tour event.

The 25-year old 2010 US Open Champion explained that his play at the last match was much better than the previous battles, resulting from a much-improved physical condition.

“Today was the first day that I felt perfect physically. So that is the most important thing,” Nadal asserted, according to The New York Times.

This displays his improved condition in the Aussie open.

Nadal was noticeably sweating buckets during his weekend battle with Australian teen ace, Bernard Tomic and also in a number of matches in the tour.

Disclaiming earlier reports that he lacks enough energy to face battles in the Australian Open, the camp of the three-major tennis tour champ clarified that Nadal has been under the weather, after catching some virus in Doha, Qatar, leaving him weak and causing him to sweat excessively.

As described by the NYT, Nadal was seen peeling off his shirt that’s unusually soaked with sweat, inevitably clinging to his body during the play.

“The two other days I was sweating like crazy and I felt very tired when I played the match,” Nadal was quoted as saying by The New York times.

The battle with Cilic who struggled in 6-2 6-4 6-3 defeat shows, claimed Nadal, that ‘he is back in business’ and ready to take on the strongest rival in the quarter-finals.

Nadal was all smiles as he described his last fight with No. 15 seed Cilic.

"I was able to play with high intensity, very good rhythm, playing more inside the court. So play more aggressive, changing rhythms with the slice and with the topspin, backhand." Nadal was quoted as saying by Sportal.com. "The serve worked better today. So, in general, I think it was a very good match for me and very important victory. So very happy for everything."

Nadal is facing fellow Spanish ace, No. 7 David Ferrer. This is the first time in years for all-Spanish match in Australian Open and Nadal noted that the match would bring pride to his country.