Top seed and defending champion David Ferrer made a winning start at the Copa Claro, with a first round success over Agustin Velotti in Buenos Aires.
The Spaniard, making his first clay court appearance of the season, broke serve four times in 79 minutes for a 6-4 6-1 win.
The only other seed in action, number six Fabio Fognini, also progressed with a 7-5 6-3 victory over Guillermo Garcia-Lopez.
The remaining two matches both guaranteed a home presence in the next round as both were all-Argentinean affairs.
Marco Trungelliti and David Nalbandian, the latter a runner-up at the Brasil Open at the weekend, were victorious, seeing off compatriots Facundo Arguello and Carlos Berlocq respectively.