Rafael Nadal returns a shot against John Isner at the China Open on Friday. Photo: Ng Han Guan/AP

BEIJING – Rafael Nadal got some fibre from a tennis ball lodged in his eye, but that did not stop the world number one setting up a China Open semi-final on Saturday with “great guy” Grigor Dimitrov.

The Spaniard tamed the big-serving American John Isner 6-4, 7-6 (7/0) on Friday to set up the clash with the third-seeded Bulgarian.

Dimitrov booked his place in the last four on Beijing’s outside hard courts with a 7-6 (7/5), 4-6, 6-2 victory over another Spaniard, Roberto Bautista Agut.

The other semi-final will be an intriguing encounter between two rising talents, with temperamental but talented Nick Kyrgios playing starlet Alexander Zverev of Germany. 

Nadal, 31, the 16-time Grand Slam champion, revved up a gear against Isner to surge through the second-set tie break, although there was concern at one point during the set when he appeared to be suffering an eye problem.

“Just something came to my eye, that’s all,” said Nadal, who is chasing a sixth title this year.

“I think it was just a hair or something, a hair from the tennis ball. It was bothering me for a while.

“Not important, (but) I am still feeling (it) a little bit by the way,” Nadal, who attempted to wash the suspected fibre out with water, added with a smile.

Nadal will face a familiar figure in Dimitrov – the pair practised together at Nadal’s base in Mallorca before the US Open, where the Spaniard won the title for a third time this year.

They even went fishing together, but Nadal said they will have their game faces on for Saturday: “At the end of the day, we are competitors.

“We go on court and we try our best, and we want to win. Of course, he is a player that I really have like a good friend on the tour. He’s a great guy.”

Kyrgios, 22, enjoyed an easy passage into the last four when Belgian qualifier Steve Darcis retired at 6-0 and 3-0 down to the Australian.

The 20-year-old Zverev, like Nadal also searching for a sixth title in a breakthrough season, had few scares in dispatching Russia’s Andrey Rublev 6-2, 6-3.