The top seed David Ferrer's had to battle to make the quarter-finals at the Heineken Tennis Open in Auckland
Germany's Tobias Kamke won the first set 6-4 before the Spaniard began playing up to his world ranking of seventh, taking the second in a tie break and the third 6-4.
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Another Spaniard, the second seed Nicolas Almagro, had fewer problems dispatching Romania's Victor Hanescu, 6-4 7-6.
The seventh and eighth seeds Brazil's Thomaz Bellucci and Philipp Kohlschrieber of Germany are also through after wins in three sets over Tommy Robredo and another Spaniard Marcel Granollers.