Nicolas Almagro fell at the first hurdle in his attempt to mount another challenge at the Barcelona Open on home soil when he was beaten by Teymuraz Gabashvili on Monday.
Almagro was appearing at the Real Club de Tenis Barcelona 1899 for the 13th year in a row and reached the final three years ago, having also advanced to the last four on three occasions.
The 30-year-old ended Rafael Nadal's 41-match winning streak in this event two years ago, but there will be no heroics this time around after he failed to win two match points and went down 1-6 7-6 (7-3) 6-2 to Georgian Gabashvili.
Gabashvili and Almagro both crashed out in the first round of the Monte Carlo Masters last week and it was the former who responded on the Catalonia clay in the first meeting between the two.
Inigo Cervantes and Albert Montanes were able to advance to the second round of the ATP World Tour 500 clay-court tournament in their homeland by seeing off Franko Skugor and Roberto Carballes Baena respectively.
Alexander Zverev showed another example of his promise with a straight-sets win against fellow German Jan-Lennard Struff.
Radek Stepanek was the highest-ranked player in action on Monday and the veteran Czech booked a second-round meeting with David Ferrer by beating Santiago Giraldo 6-4 7-5.
Stepanek had to come through qualifying matches against Gerard Granollers and Christian Garin to earn a place in the first round.
Monday's action also saw wins for Evgeny Donskoy, Malek Jaziri, Karen Khachanov and Victor Estrella.