Estoril - South Africa's Kevin Anderson joined the exodus of Estoril Open seeds Thursday when he slumped to a 6-4, 3-6, 6-1 defeat to Spain's Guillermo Garcia-Lopez on the back of nine double faults.
The exit of second-seeded Anderson left the rebranded clay court event without its top four players even before the quarter-final stage.
Top seed Feliciano Lopez lost 24 hours earlier, number three Tommy Robredo withdrew injured while fourth seed Leonardo Mayer was another early victim.
Fifth-seeded Frenchman Richard Gasquet, a finalist in 2007 and 2012, remains the highest seed still in contention along with number seven Nick Kyrgios and number eight Gilles Muller.
Anderson went down in just over two hours, losing serve three times but crushed mainly by his serving errors.
He contributed his last double-fault in the penultimate game on a break point to trail 5-1 before being put out of his misery a game later.
Anderson has reached the semi-finals or better four times this year and now stands 33-31 on clay for his career.
The 31st-ranked Garcia-Lopez owns titles this season at Zagreb and won on clay in Bucharest last weekend. He now stands 18-8 in 2015 and 7-1 on clay.
He was one of four Spaniards playing on Thursday and will face the winner of a later match between the last of the Portuguese players, Rui Machado, and Croatian teenager Borna Coric.
Garcia-Lopez's best Estoril showings were semi-finals in 2005 and 2010.
"I'm delighted with the win, especially since last week I also won a tournament," said Garcia-Lopez.
"It's not easy, especially since I'm pretty tired. The first match of a tournament is always difficult and Anderson is a very aggressive player."
"I'm playing with confidence right now and hope to win another round or two."
Spain's Pablo Carreno Busta beat compatriot David Vega Hernandez, who replaced Robredo in the draw, 6-1, 6-2.
Results on the third day of the Estoril Open on Thursday (x denotes seeded player):
Pablo Carreno-Busta (ESP) bt David Vega (ESP) 6-1, 6-2
Guillermo Garcia-Lopez (ESP) bt Kevin Anderson (RSA x2) 6-4, 3-6, 6-1