Rafael Nadal has come from behind against hard-hitting Jack Sock to reach the China Open semi-finals and set up a rematch with his shock US Open conqueror Fabio Fognini.

The Spanish great, scrapping to recover his form after a tough year, was frequently outgunned by the American’s forehand but he dug deep to see off the world number 30, 3-6 6-4 6-3.

“Yes, it was an important victory for me. Obviously I finished the match playing better than what I started. It’s important because I came back,” Nadal said.

“This year I lost a lot of matches when I had an advantage. So to have the chance to win a match when I start losing this one, so it’s important for me, too.

“It’s an important thing, important fact that I finished the match playing better than what I started. That is a positive thing for my game.”

Nadal had not reached a hardcourt semi-final for more than a year, but he will now play Fognini, who stunned him last month in the US Open third round, for a place in the title match.

“He’s a great player. When you play against a great player, especially if you don’t play to your best, your chances are lower,” Nadal said of the Italian, who beat Uruguay’s Pablo Cuevas 6-1 2-6 6-2.

“If I am able to play my best tomorrow … I am going to have my chances. If not, it’s going to be tough. It’s simple. Sport is simple.”

Meanwhile in the women’s last eight, Agnieszka Radwanska beat Angelique Kerber 6-1 6-4, and Timea Backsinszky bounced back to beat Sara Errani 0-6 6-3 7-5.

In the other men’s quarter-finals, unbeaten five-time champion Novak Djokovic is playing America’s John Isner later, while Spanish fourth seed David Ferrer takes on Taiwanese wildcard Lu Yen-hsun.