David Goffin made a comprehensive start to his campaign at the Abierto Mexicano Telcel but fellow seed John Isner fell at the first hurdle.
Belgian fifth Goffin seed needed just 54 minutes to see off Stephane Robert in straight sets in Acapulco on Monday.
A quarter-finalist at the Australian Open this year, Goffin - who posted six aces while not facing a break point throughout - eased to a 6-1 6-2 victory as he reached the second round at the ATP 500 tournament in Mexico.
Goffin - a finalist in Sofia and Rotterdam this season - will face either Kyle Edmund or Sam Querrey in the next round.
Towering American and eighth seed Isner was not so fortunate in the first round, bundled out by countryman Steve Johnson.
Isner did not earn a break point while he was broken twice in a 6-4 6-4 loss.
Next up for Johnson is Ernesto Escobedo, who beat Stefan Kozlov 6-1 2-6 6-0.
Talented Croatian Borna Coric won 91 per cent of his first serves in a 6-1 6-1 demolition of qualifier Lucas Gomez.
Adrian Mannarino overcame Taylor Fritz 3-6 7-6 (7-5) 6-4, while Jordan Thompson stunned Feliciano Lopez 2-6 6-3 6-3.