Seeds struggle in Zagreb
Third seed Ivo Karlovic was ousted by defending champion Sergiy Stakhovsky in the second round of the Zagreb Open on Thursday.
World No.84 Stakhovsky won his first ATP World Tour title last year in the Zagreb Open when he defeated Ivan Ljubicic in the final.
Frenchman Paul-Henri Mathieu also suffered a shock defeat as world No.78 Jan Hernych rallied past the world No.34 6-7, 6-4, 6-2. Hernych now faces Germanys Mischa Zverev who triumphed over Romanias Victor Hanescu.
There was better news for seventh seed Mario Ancic has he demolished Russias Teimuraz Gabashvili, 6-1, 6-1, to reach the quarter-finals. Ancic now faces Croatian qualifier Ivan Dodig, who continued his surprise run by edging past Latvian Ernests Gulbis 7-6, 6-4.
At the Movistar Open in Chile Spains No.2, Tommy Robredo, earned his first victory of the tournament prevailing over Argentine Brian Dabul 6-3, 7-6. Robredo will now face Juan Ignacio Chela; Robredo is yet to drop a set against Chela on clay.
Elsewhere in the Zagreb Open draw, No.4 seed and 2006 champion Jose Acasuso advanced with a 7-6, 6-3 win over Thomaz Bellucci of Brazil. Acasuso is now up against lucky loser Sebastian Decoud. This will be the Argentines first ATP World Tour quarter-final.
At the SA Open in Johannesburg, seeds sailed through on Thursday of the ATP World Tour event.
Top-seeded Frenchman Jo-Wilfried Tsonga defeated Denis Istomin of Uzbekistan 6-1, 6-4 in just over an hour. Tsonga is vying for his fourth ATP World Tour title.
Fourth seed Spaniard Guillermo Garcia-Lopez knocked out Leonardo Mayer of Argentina 6-4, 7-5. Garcia-Lopez will next play Federico Gil of Portugal who battled past local boy and wild card Rik de Voest, 4-6, 7-5, 6-4.
Fifth seed Jeremy Chardy, French qualifier Sebastian de Chaunac and seventh seed Belgian Kristof Vliegen are also through in South Africa.