Novak Djokovic and Rafael Nadal enjoyed contrasting wins as they advanced to the Abierto Mexicano Telcel quarter-finals.
Former world number one and top seed Djokovic had to dig deep against Juan Martin del Potro, rallying from a set down to win in three on Wednesday.
Djokovic - seeking to reach his first final at the ATP 500 event - triumphed 4-6 6-4 6-4 over the 2009 US Open champion in Acapulco.
The Serbian star broke in the 10th and final game as he closed out the second-round clash in two hours, 38 minutes to set up a meeting with sixth seed Nick Kyrgios, who saw off Donald Young 6-2 6-4
Nadal remains on track for a third title in the Mexican city after blitzing Paolo Lorenzi 6-1 6-1.
The 14-time grand-slam champion and second seed eased past the Italian in just 66 minutes as he improved to 12-0 at the tournament.
Nadal was in a relentless mood, breaking five times and only losing seven points on his serve throughout the straight-sets win.
Next up for Nadal is Japan's Yoshihito Nishioka, who overcame Jordan Thompson 6-4 3-6 6-0.
Defending champion and fourth seed Dominic Thiem accounted for Adrian Mannarino 7-5 6-3.
Marin Cilic emerged triumphant 6-3 2-6 6-3 in his all-Croatian affair against Borna Coric.
After firing down 12 aces, 2014 US Open winner Cilic will take on Steve Johnson in the quarter-finals after the American beat countryman Ernesto Escobedo 7-6 (7-5) 6-3.
Belgian fifth seed David Goffin was not so fortunate, surprisingly eliminated 6-2 6-3 by Sam Querrey.
Meanwhile at the Brasil Open, Albert-Ramos Vinolas, Joao Sousa and Federico Delbonis progressed to the last eight.
Spanish second seed Vinolas defeated Gastao Elias 6-4 7-6 (7-5), fourth-seeded Portuguese Sousa was too good for Renzo Olivo 6-2 6-4 and Argentine seventh seed Delbonis overcame Casper Ruud 7-5 6-3.
However, Carlos Berlocq - the eighth seed - lost 7-5 6-3 to fellow Argentinian Guido Pella.