Rafael Nadal defeated Karen Khachanov in straight sets to set up a China Open quarter-final clash against John Isner on Friday.

Nadal marches on in China

Nadal marches on in China

The 31-year-old Spanish world number one, who had already defeated Lucas Pouille in the hardcourt tournament in Beijing, eased past his 21-year-old Russian opponent on Thursday.

Nadal broke Khachanov in the fourth game of the opening set and never looked back as he recorded a 6-3 6-3 win.

He will now face big-hitting American Isner, who thrashed Leonardo Mayer 6-0 6-3 to book his place in the last-eight of the tournament.

And, having watched that encounter, Nadal is expecting a difficult time against the 32-year-old world number 17.

He said: "Happy about the match today. I think I played a solid match.

"Tomorrow will be a tough one against Isner - he's playing unbelievably well. “I saw his match today. He played huge.

"So let's see what's going on tomorrow."