"Its better like this than having long matches".
"It doesn't matter how long you are on court, (the) most important thing is be enough competitive to (handle) all the situations".
Dimitrov, chasing a spot at the season-ending ATP Finals in London, beat American Sam Querrey 6-3, 7-6 (3) to set up a Chinese reunion with Nadal.
The 20-year-old Zverev, who has collected 5 ATP World Tour titles this season, lost his temper when broken by the Argentine at 2-2 in the decider and flung his racquet down to the ground, reports Xinhua news agency.
Zverev, the world No.4, was beaten in three sets 3-6 7-6 6-4 by Del Potro in China in the third-round clash and he admitted afterwards that he'd come up against an in-form opponent, while he stressed he had done plenty right in the game as well.
Del Potro, who lost his serve for the only time in the match in the second game, won nine of his 15 service games at love. He repeatedly smashed his racket until it was a mangled mess.
"I played a very good match, I don't know how many mistakes I made, but very few", said the 16-time Grand Slam victor and top seed in Shanghai.
Del Potro will John Isner of the USA or Viktor Troicki of Serbia in the last eight on Friday.
"I just had to be there (on those match points)", Dimitrov said.
Fourth seed Marin Cilic of Croatia and Spain's Albert Ramos-Vinolas go head to head in the other quarterfinal.