Madrid, Spain, 11 May 2017 | AAP

The toughest assignment in men’s tennis – Rafael Nadal on clay – looms next for Nick Kyrgios after a breezy win by the Australian at the Madrid Open on Wednesday.

Kyrgios did what his compatriot Bernard Tomic on Tuesday could not – down American Ryan Harrison.

And the lanky Canberran did it with almost Roger Federer-like ease in the 6-3 6-3 victory that took little over an hour.

Nadal though did not have it all his own way and took nearly three hours to put away enigmatic Italian Fabio Fognini 7-6(3) 3-6 6-4 and he was left fuming by his sub-par performance.

“Even though I played really badly, my attitude has been very positive,” Nadal said.

Nadal prior to the Fognini match had looked to be in imperious touch after winning back-to-back titles in Monte Carlo and Barcelona.

He’s won 10 straight matches, lost just one set in that time and now has an all-time record of 51 claycourt titles, which may well become 52 by week’s end.

But Kyrgios looks to be improving all the time on the surface, has a claycourt final to his name in Estoril in 2015 and pinched a set off Nadal in their round-of-16 clash in Rome last year.

He also won their only other encounter at Wimbledon in 2014.

There’s also further impetus for Kyrgios to do well.

A delayed start to the clay court season after the death of his grandfather has seen Kyrgios drop to No.20 in the world.

A move back into the top 16 by the French Open would be useful for the two-time Grand Slam quarterfinalist, ensuring he avoids anyone seeded higher than him until at least the fourth round.