Former Barcelona Open finalists Nicolas Almagro and Santiago Giraldo were both knocked out in the opening round of this year's tournament.
Home favourite Almagro, who finished runner-up to Rafael Nadal in 2013, had two match points against Teymuraz Gabashvili, but the Russian staged a comeback to win 1-6 7-6 6-2.
Colombian Santiago Giraldo, the finalist two years ago, was sent packing by Czech qualifier Radek Stepanek 6-4 7-5.
Rising German star Alexander Zverev beat qualifier Jan-Lennard Struff 6-4 6-3.
Zverev will face Brazil's world number 35 Thomaz Bellucci on Wednesday, the teenager's 19th birthday.
Spain's Inigo Cervantes and Albert Montanes reached the second round with victories over Franko Skugor and Roberto Carballes respectively.
Source: PA
