Last year's runner-up Carlos Berlocq was an easy first-round winner Tuesday at the $410,000 VTR Open.
The eighth-seeded Berlocq blew past Russian Andrey Kuznetsov 6-2, 6-1 on the red clay at Club Naval de Campo Las Salinas.
Berlocq lost to Juan Monaco in last year's all-Argentine Vina del Mar finale.
Vina del Mar local and two-time runner-up Nicolas Massu, however, dropped a 6-7 (6-8), 6-3, 6-4 decision to Spain's Albert Montanes on Tuesday.
The 33-year-old Chilean hit 10 double faults, while Montanes reeled off eight aces and broke Massu's serve four times to advance.
Montanes reached the final here back in 2007.
Also on Tuesday, Frenchman Guillaume Rufin handled Spaniard Ruben Ramirez Hidalgo 6-3, 6-4; Chilean teenage wild card Christian Garin doused Serbian qualifier Dusan Lajovic 6-3, 6-4; Horacio Zeballos came back to top qualifier and fellow Argentine Diego Sebastian Schwartzman 1-6, 6-2, 6-2; and former world No. 5 and 2011 VTR Open titlist Tommy Robredo drilled fellow Spaniard Pere Riba 6-2, 6-2. Garin is a 16-year-old making his ATP World Tour debut this week. Rufin will face the reigning champion Monaco in the round of 16.
The top seeds here are Rafael Nadal and the reigning champion Monaco, who is Nadal's doubles partner this week. Both players received opening-round singles byes, but won their opening doubles match Tuesday, 6-3, 6-2, against a duo of Frantisek Cermak and Lukas Dlouhy.
Nadal is playing his first tennis since last June after being sidelined with a knee injury. The Spanish great, who owns 11 Grand Slam titles, including a record seven French Open championships in the Open Era, is appearing in a South American tournament for the first time since 2005, when he won a title in Brazil as an 18-year-old.
The former world No. 1 Nadal will open his singles Vina del Mar stay on Wednesday against qualifier Federico Delbonis, who fought back to best fellow Argentine Guido Pella, 2-6, 7-6 (7-4), 7-6 (7-1), on Day 1.
This week's winner will collect $74,000.