Rafael Nadal said he was braced for the "huge" serve of John Isner after Spain's world number one bulldozed his way into the China Open quarter-finals on Thursday. The 16-time Grand Slam champion Nadal saw off the young Russian Karen Khachanov 6-3, 6-3 to set up a clash with Isner in Beijing. They are joined in the last eight by second seed Alexander Zverev, the rising German star who beat Italy's Fabio Fognini 6-4, 6-2 in the final match of the day. The in-form Isner, the American sixth seed, is renowned for his booming service game and Nadal expects to come under a barrage on Friday. Isner was impressive in blasting his way past Argentina's Leonardo Mayer 6-0, 6-3 and Nadal said: "Tomorrow will be a tough one against Isner, he's playing unbelievably well.

Rafael Nadal