Rafael Nadal falls to Nick Kyrgios in Cincinnati quarters after Cincinnati double-header

Kyrgios made light work of Nadal, winning by 6-2 7-5 in around one hour and 20 minutes.

Spekaing after the match, the Spaniard told reporters: "He obviously is a tough match always...Nick is a great player, but I played poorly.

"I started the match well and then I played a very bad game in the second set when he broke me. I played some good points. He had some mistakes and I was able to be back in the match. And then I played a terrible game. So it was a bad match for me."

Australian Kyrgios hit 10 aces against the 15-time grand-slam winner to set up a semi-final against David Ferrer, who produced another shocking result in dominating third-seed Dominic Thiem 6-3 6-3.

Both Nadal and Kyrgios had played earlier in the day, to complete Thursday's rained-off matches. 22-year-old Kyrgios had defeating hard-serving 6-foot 11-inch Ivo Karlovic of Croatia 4-6 7-6(6) 6-3.

Kyrgios, who looked more composed against Nadal, threw his racquet down in disgust after losing two straight service points in the second-set tie-break against Karlovic.

Meanwhile a slightly rusty Nadal beat compatriot Albert Ramos-Vinolas 7-6(1) 6-2 earlier in the day.

Despite the defeat, the 31-year-old Nadal will for the fourth time in his career be the world number one when the ATP rankings come out next week.

On the other side of the draw, red-hot American John Isner beat countryman Jared Donaldson 7-6(4) 7-5 to set up a semi-final against seventh-seeded Bulgarian Grigor Dimitrov, who sailed past Japan's Yuichi Sugita 6-2 6-1.

Nick Kyrgios (Australia) beat 1-Rafa Nadal (Spain) 6-2 7-5

David Ferrer (Spain) beat 3-Dominic Thiem (Austria) 6-3 6-3

7-Grigor Dimitrov (Bulgaria) beat Yuichi Sugita (Japan) 6-2 6-1

14-John Isner (U.S.) beat Jared Donaldson (U.S.) 7-6(4) 7-5

1-Rafa Nadal (Spain) beat Albert Ramos (Spain) 7-6(1) 6-2

Nick Kyrgios (Australia) beat Ivo Karlovic (Croatia) 4-6 7-6(6) 6-3