The 93rd-ranked Brazilian, who next plays fifth-seeded Federico Delbonis of Argentina, won two of his three career titles on clay in the Swiss mountains, in 2009 and 2012.
Sixth-seeded Gilles Simon was unable to complete his first-round match due to a back injury. The Frenchman retired when trailing 6-2, 3-2 against Pablo Andujar of Spain.
Swiss wild card Yann Marti beat Daniel Gimeno-Traver of Spain in a match held over from Monday evening, when darkness forced play to be suspended.
Resuming at 5-5 in the deciding set, the 212th-ranked Marti beat Gimeno-Traver 5-7, 7-6 (7), 7-6 (5).
Also Tuesday, Blaz Rola of Slovenia beat Brazil's Fabiano De Paula 6-4, 6-4 and Jan-Lennard Struff of Germany advanced due to another injury retirement. Struff led Andreas Haider-Maurer 6-2, 1-0 when the Austrian could not continue.