Number four seed Fernando Verdasco crashed out of the Ecuador Open in Quito, losing in three sets to Argentinian Renzo Olivio.
The Spaniard, who beat Rafa Nadal in last month's Australian Open, was humbled in his first outing in the tournament as Olivio won 7-6 3-6 6-3 in just under two hours.
Olivio's prize is a quarter-final with Victor Estrella Burgos, who raced past Andrej Martin in a 7-5 6-1 victory.
Number two seed Feliciano Lopez also had trouble on the clay but eventually had enough to beat Brazilian Joao Souza.
Lopez, who was two points away from defeat, came from a set down to win 4-6 7-6 6-2.
The Spaniard will play compatriot Albert Ramos-Vinolas in the last eight after the latter booked his spot with a hard-fought 6-7 6-3 7-5 win over Rajeev Ram.
Bernard Tomic against Paolo Lorenzi and Thomaz Belluci versus Pablo Carreno Busta make up the other last-eight ties, with none of those four players taking the court on Thursday.
Source: PA
