The 31-year-old Spaniard Nadal, fresh off the back of triumphs at the US Open and China Open, anticipates a tough encounter against the Bulgarian Dimitrov.
"For me, it's impossible to lose a match when I've only been broken one time", Zverev said.
Bedene retired at the China Open during the last 16 match with Spain's Roberto Bautista Agut.
Earlier on Thursday, Grigor Dimitrov booked his place in the quarter-finals, downing Sam Querrey 6-3 7-6 (7-3).
Federer will play Richard Gasquet in the quarterfinals.
A mouthwatering Nadal-Federer final on Sunday awaits if the celebrated pair continues at the current rate.
Del Potro, the 2013 Shanghai Masters runner-up, will face either American no. 12 seed John Isner or Viktor Troicki of Serbia on Friday.
Zverev's fury at letting the match slip became apparent in the third as he massacred his racquet as the Argentine broke for a 3-2 lead in the decider.
Third seed Zverev was a different matter, though, and, after losing the first four games, Bedene accepted he would not be able to compete and shook hands.
A fan at least came away with a demolished racquet for a souvenir after the young German handed it to a spectator.
Zverev, 20, has already qualified for the ATP World Tour Finals at the O2 next month but is yet to decide if he will play in the NextGen Finals in Milan, the new ATP tournament featuring the world's top 21-and-under singles players across the ATP World Tour season. "I think we both played pretty well from the baseline".
"I just had to be there (on those match points)", Dimitrov said.
"I saw his frustration, for sure".