Top seed Nikolay Davydenko of Russia and Spaniards David Ferrer and Juan Carlos Ferrero fell in a trio of first round shocks at the Valencia Open on Tuesday.
Davydenko, who had pulled out of his singles rubber on Sunday in Russia's Davis Cup quarter-final win over France due to injury, lost 7-5, 7-5 to Czech opponent Jan Hernych on the Spanish clay.
Another of Russia's Davis Cup players, wild card entrant Marat Safin, enjoyed a 7-6, 6-4 victory over his compatriot Igor Andreev.
Ferrer, the third seed, retired with back pain after losing a first set tiebreak against France's Thierry Ascione 7-1.
In another upset Spain's Nicolas Almagro defeated former world number one Ferrero, the fourth seed, 6-7, 6-4, 6-4 to reach the second round.
(Writing by Bill Barclay in London)