Alexander Zverev faces Juan Martin del Potro in Round of 16.
Del Potro then secured the all-important break in the fifth game of the final set, going on to close out the match after nearly two hours on court. "I was feeling good the whole match, even coming out of the first set, which he was playing well". "This was a positive for me looking to the future". Grigor broke back in the very next game, also at love, when Querrey's volley landed long, and they were now back on the level terms.
Zverev whacked his racket on the court.
"For me, it's impossible to lose a match when I've only been broken one time", Zverev said. "I just had to find my way through the whole match".
World No 16 Del Potro previously reached the final of the Shanghai Masters in 2013 before losing to Novak Djokovic.
"I saw his frustration, for sure", he said. "He has everything to be in the top of the game".
The 6th seed Grigor Dimitrov never passed the second round here in Shanghai before and he is now the quarter-finalist, after a 6-3 7-6 triumph against Sam Querrey in 80 minutes. Fourth-seeded Marin Cilic defeated another American, Steve Johnson, 7-6 (1), 6-4.