Del Potro outlasts Ferrer as Zverev and Thiem advance
Juan Martin del Potro prevailed against a feisty David Ferrer to book a quarter-final meeting with third seed Dominic Thiem at the Mexican Open.
Del Potro made it through to the next round by outlasting Spanish veteran Ferrer 6-4 4-6 6-3 in Acapulco on Wednesday.
The Argentine sixth seed won the opening set but Ferrer showed his trademark fighting spirit as he rallied to force a decider.
But 2009 US Open champion Del Potro was not to be denied his first last-eight appearance at the ATP 500 tournament.
It does not get any easier for Del Potro, who will face 2016 winner Thiem for a spot in the semi-finals.
Thiem made light work of Canada's teenage sensation Denis Shapovalov 6-2 6-3 in just 75 minutes on the Mexican hard courts.
The Austrian star benefited from a wasteful Shapovalov, who tallied 20 unforced errors as Thiem cruised through.
World number five and second seed Alexander Zverev saw off fellow German Peter Gojowczyk 7-6 (8-6) 6-3 to reach the quarters.
Zverev - the highest-ranked player remaining in the draw following Rafael Nadal's withdrawal - fended off three set points in the opener before breaking at 4-3 in the second.
Ryan Harrison awaits after the American trumped in-form Diego Schwartzman 6-3 5-7 6-4.
Australian Open semi-finalist Hyeon Chung was too good for Ernesto Escobedo 6-3 6-1 as he set up a showdown with fifth seed Kevin Anderson, who defeated Adrian Mannarino 6-3 6-4.
Meanwhile, Jared Donaldson beat Matthew Ebden 6-3 6-1 and Feliciano Lopez eliminated Thanasi Kokkinakis 6-3 6-4.
At the Brasil Open, three-time reigning champion Pablo Cuevas extended his winning streak in Sao Paulo to 14 matches with a 6-4 7-6 (7-4) victory over Sebastian Ofner en route to the quarter-finals.
Leonardo Mayer - the fifth seed - overcame Carlos Berlocq 7-5 6-4, second seed Fabio Fognini accounted for Joao Domingues 7-5 6-1, while Guillermo Garcia-Lopez topped 2014 champion Federico Delbonis 7-6 (7-3) 4-6 6-4.