Argentine Juan Martin Del Potro edged out American James Blake 6-4 7-6 in the second round of the Farmers Classic in Los Angeles on Wednesday evening.

27262 - Del Potro overcomes Blake to make quarters

The second-seeded Del Potro broke Blake in the fifth game of the opening set, before securing his passage to the quarter-finals by taking out the second-set tiebreak 7-3. A dejected Blake left the court without waving to the fans, and will now likely need a wildcard in order to enter the main draw of the upcoming US Open.

In the final eight, Del Potro will take on Latvian Ernests Gulbis, who breezed by qualifier Daniel Kosakowski 6-2 6-4.

In Wednesday's other matches at the Farmers Classic, Yen-Hsun Lu created an upset and was far too strong for third seed Marcos Baghdatis, as he took just over an hour to record a 6-3 6-4 victory over the Cypriot.

American Ryan Harrison also enjoyed a straight sets victory over compatriot Michael Russell, winning 6-3 6-4 to set up a quarter-final clash with Lu.

Elsewhere, at the Swiss Open, No. 3 seed Mikhail Youzhny overcame Uzbek Denis Istomin 6-3 6-2 in their second-round encounter, as Germany's Matthias Bachinger ousted seventh seed Pablo Andujar in convincing fashion in their first-round match 6-1 6-4.

Marcel Granollers from Spain was leading Igor Andreev 6-4 4-3, and Santiago Giraldo was holding a 6-3 2-2 advantage over Andreas Haider-Maurer of Austria when rain stopped play.

Meanwhile, in the second round at the Croatian Open, Juan Carlos Ferrero notched a valiant 1-6 6-3 6-4 win over Ivan Ljubicic and second seed Alexandr Dolgopolov eased to a 6-1 6-2 triumph over Italian Filippo Volandri in just 55 minutes.