David Ferrer led the way as the leading lights all progressed to the third round of the Copa Claro in Buenos Aires.
The top seed overcame a slow start to beat the dangerous David Nalbandian 2-6 6-4 6-0.
Fellow Spaniard Nicolas Almagro had things a little easier as the second seed saw off Andrey Kuznetsov 7-6 (7-5) 6-2.
In fact there will be a distinctive Spanish feeling to the third round after Albert Ramos and Tommy Robredo came through in straight sets.
Eighth seed Ramos defeated Leonardo Mayer 6-3 7-6 (7-3), while Robredo came past Diego Sebastian Schwartzmann 6-3 6-1.
No 3 seed Stanislas Wawrinka registered a routine 6-1 6-4 win over another Spaniard in Daniel Gimeno-Traver, while sixth-ranked Fabio Fognini was a 7-5 6-2 victor against Marco Trungelliti.
Unseeded duo Julian Reister and Federico Del Bonis also booked their places in the next stage, recording wins over Aljaz Bedene and Albert Montanes respectively.