(CNN) -- Top seed and defending champion Andy Murray has crashed out of the Valencia Open at the second round stage, beaten in three sets by 12th seed Juan Monaco.
The Briton went into the encounter having won his last six matches without dropping a set, but he struggled throughout and eventually lost 6-2 3-6 6-2.
Murray had beaten Spaniard Monaco on his way to victory in the Shanghai Masters last month but failed to find his normal level on Wednesday -- losing his first eight points en route to defeat.
And Murray was soon followed by third seed Fernando Verdasco, who disappointed his home crowd with a heavy 6-1 6-3 defeat at the hands of Gilles Simon.
Eighth seed Gael Monfils reached the second round with a 6-3 6-3 victory over Argentine Eduardo Schwank, while there was disappointment for last year's Valencia runner-up Mikhail Youzhny, who was forced to withdraw through injury before his match with Pablo Cuevas.
Elsewhere, top seed Roger Federer delighted his home crowd by reaching the quarterfinals of the Swiss Indoor tournament in Basel with a straight sets victory over Serb Janko Tipsarevic.
Federer remains on course for his fourth tournament success in the last five years with a 6-3 6-4 win and is joined in the last eight by Dutchman Robin Haase, who shocked eighth seed John Isner 6-2 6-7 7-5.
Fourth seed Andy Roddick reached the second round, staying in the hunt for a place in the World Tour Finals in London in the process, with a 7-5 7-6 defeat of fellow-American Sam Querrey.
Three places still remain in the eight-man field, with Roddick currently occupying the final one of those positions.
Rafael Nadal, Federer, Novak Djokovic, Murray and Robin Soderling have all already secured their places.