Top seed David Ferrer cruised through his opening match at the Malaysian Open in Kuala Lumpur, beating Alex Bogomolov Jr 6-4 6-2.
The world number five took time to find his form but was well on top in the second set to record his 61st victory of the season, equalling Roger Federer's mark.
"It was a difficult match. The first set was close but after winning it, I felt better," said Ferrer, who broke four times in total. "I was more consistent in the second and also a bit more relaxed."
Second seed Juan Monaco produced a spluttering performance in beating wild card Jimmy Wang and reach the last eight.
The Argentine, making his tournament debut, lost his serve three times before edging past the Taiwanese star 6-4 7-5 to book a date with Canada's Vasek Pospisil.
Monaco, 28, hit back with five breaks from 11 opportunities to clinch victory in one hour and 48 minutes and move closer to a fourth title in 2012.
Russian Nikolay Davydenko, former world No 3, looked relatively comfortable in Kuala Lumpur with a 7-5 6-4 win over Denis Istomin of Uzbekistan.
The 31-year-old Davydenko will next face third-seed Kei Nishikori of Japan who was given a fright by Spain's Albert Ramos, losing the first set on a tie-break before coming back strongly to win 6-7 6-2 6-1.