Teymuraz Gabashvili came through his first-round clash with Pablo Carreno Busta at the Barcelona Open to set up a meeting with top seed Kei Nishikori.
The Russian made the most of five double-faults from home favourite Carreno Busta to seal a 7-5 6-4 success in Catalonia and ensure a tricky test against defending champion Nishikori.
Earlier, wildcard Roberto Carballes Baena had caused spring a surprise with victory over Jan-Lennard Struff - the Spanish wildcard fighting from a set down to progress 5-7 7-5 6-2 with only his fourth tour-level win.
Despite 150 places separating the pair in the world rankings, the Spaniard recovered from a narrow first-set defeat to break twice in the second and level up.
The 22-year-old took that motivation into the decider and, having moved 5-1 ahead, closed out the win and ensured a clash with Uruguayan 10th seed Pablo Cuevas next up.
World number 54 Mikhail Kukushkin needed just 53 minutes to brush aside Brazil's Joao Souza 6-1 6-0 in their first career meeting.
In a match devoid of aces, Kukushkin converted five of eight break-points to set up a second-round meeting with ninth seed Tommy Robredo.
Souza's compatriot Thomaz Bellucci fared better, winning by the same scoreline against qualifier Yuichi Sugita.
The Japanese world number 140 was broken six times in the 49-minute rout while Andrey Kuznetsov and Benoit Paire secured progression in straight-sets against Marton Fucsovics and Jaume Munar respectively.
The all-Spanish affair between Pablo Andujar and Albert Ramos-Vinolas saw the former win through 6-4 6-1 while wildcard Elias Ymer overcame qualifier Thiemo de Bakker 6-7 (4-7) 7-5 6-4.
Marcel Granollers-Pujol saved five of seven break-points on his way to a 6-2 6-3 success against Australia's Marinko Matosevic.