No seeds advanced to the second round of the Ecuador Open on Monday as Horacio Zeballos and Thiago Monteiro crashed out.
Argentine sixth seed Zeballos was the first casualty in Quito, upstaged by Gerald Melzer in three sets.
Melzer served up 14 aces and converted one break point as he stunned Zeballos 6-7 (4-7) 6-3 7-6 (7-4) at the ATP 250 event.
Brazilian seventh seed Monteiro also fell at the first hurdle following a straight-set defeat to local wildcard Giovanni Lapentti.
Monteiro was no match for Lapentti, who claimed four breaks and fended off two of his own in a 6-3 6-2 triumph.
Elsewhere, 2011 and 2012 US Open quarter-finalist Janko Tipsarevic progressed after opponent Daniel Gimeno-Traver retired when trailing 4-1 in the first set.
Santiago Giraldo accounted for Benjamin Becker 6-4 6-4.