Andy Murray reached the quarter-finals of the Abierto Mexicano Telcel in Acapulco on Wednesday night with a 6-3 6-4 victory over Joao Sousa.
The Wimbledon champion struggled with his first serve throughout, but won 72 per cent of points on his second serve to keep himself in the box seat.
He converted only three of the nine break-point opportunities he mustered, but that proved enough to see off the Portuguese number one in straight sets and secured the Scot a last-eight encounter with Frenchman Gilles Simon.
Elsewhere, it was a good day for seeds as David Ferrer - the top-ranked player in the tournament - progressed, along with Grigor Dimitrov (four), Kevin Anderson (five), Simon (six) and Ernests Gulbis (seven).
Ferrer was a 7-6 (7/1) 6-2 winner over fellow Spaniard Feliciano Lopez.
The players were evenly matched until the top seed raced through a first-set tie-break, and that appeared to break Lopez's resistance.
Anderson also needed a first-set tie-break to help him on his way to a 7-6 (7/2) 6-4 victory over American Sam Querrey.
The South African's success was built on his serve - he lost only three points on first serve all match - while he also came up clutch in the second set, converting the only break point he created.
Dimitrov and Simon were straight-sets winners - with the former beating Marcos Baghdatis 6-1 6-4 and the Frenchman overcoming Donald Young 6-4 6-3 - but life was a little tougher for Gulbis.
The Latvian was pushed all the way Belgium's David Goffin but eventually prevailed 6-1 3-6 7-6 (7/5).
There were also wins for Ivo Karlovic and Alexandr Dolgopolov.
The top three seeds in the women's draw also won.
Number one seed Dominika Cibulkova was a 7-5 6-2 winner over Yanina Wickmayer, while Canada's Eugenie Bouchard (two) beat Lara Arruabarrena by the same scoreline.
Third seed Kaia Kanepi was pushed harder by Julia Goerges of Germany before sealing a 6-7 (4/7) 6-4 7-6 (8/6) triumph.
One seed did fall though - Bojana Jovanovski of Serbia slipped to a 6-1 6-4 loss against New Zealand's Marina Erakovic.
There were also wins for Zhang Shuai, Ajla Tomljanovic, Christina McHale and Caroline Garcia.