Gael Monfils and Fernando Verdasco moved into the Argentina Open second round with straight-sets wins on Tuesday.
Unseeded at the ATP 250 event in Buenos Aires, Monfils was too good for Pablo Cuevas 6-1 6-4 in their first-round clash.
The Frenchman converted all three of his break points against the seventh seed to advance after just 65 minutes.
Verdasco, the eighth seed at the clay-court event, overcame Brazilian Thiago Monteiro 6-2 7-5.
The only other seed in action was Diego Schwartzman, who powered past Andreas Haider-Maurer 6-4 6-3.
Fresh off winning his first ATP World Tour title in Ecuador, Roberto Carballes Baena was downed in the first round, beaten 6-2 6-4 by lucky loser Gastao Elias.
Locals Horacio Zeballos and Leonardo Mayer advanced, the former crushing qualifier Marco Cecchinato 6-1 6-4 and the latter battling past Rogerio Dutra Silva 6-7 (4-7) 6-2 6-4.
Meanwhile, Aljaz Bedene needed just 62 minutes to beat Jiri Vesely 6-0 6-3.