Novak Djokovic says he is still struggling for form despite beating Mischa Zverev to make the semi-finals of the Shanghai Masters.
The world number one has endured a difficult summer but had cruised through to the last eight without dropping a set.
However, he suffered a scare as Zverev won the opening set but after levelling via a tie-break, won the decider to take a 3-6 7-6 6-3 triumph.
He will now face Roberto Bautista-Agut in Saturday's semi-finals, after the Spaniard got the better of Frenchman Jo-Wilfried Tsonga 6-3 6-4.
Defending champion Djokovic admitted he was far from at his best on Friday and that he rode his luck at times at the Qizhong Stadium.
"I wasn't striking the ball very well from the beginning of the match, to be honest," Djokovic said. "I was quite flat with my feet, so he got me where he wanted to get me, and to stand still at the baseline.
"He was fighting. He was focused. He gave his best, and he was a few points from winning."