SYDNEY, Jan. 8 (UPI) -- Top-seeded Juan Martin del Potro escaped the upset bug that took out four other seeded players Wednesday at the Apia International Sydney tennis tournament.
Del Potro lost his serve twice in the first set of a 1-6, 6-3, 6-4 decision over Nicolas Mahut. He had 14 of his 15 aces and won nearly two-thirds of the points on serve the rest of the way.
No. 4-seeded Dmitry Tursunov also needed three sets to get by Lukas Rosol 3-6, 6-3, 6-3 as seeded players went 2-4 Wednesday in the second round in Sydney.
Alexandr Dolgopolov roared past second-seeded Jerzy Janowicz 6-2, 6-2 in 56 minutes. Dolgopolov lost only seven points in eight games serving and broke Janowicz's serve four times.
Marinko Matosevic also didn't drop serve in a 6-3, 6-4 upset of third-seeded Andreas Seppi while Sergiy Stakhovsky took out No. 6-seeded Julien Benneteau 6-3, 6-2 and Denis Istomin was a 6-3, 6-4 winner over Marin Cilic, the No. 7 seed.
Radek Stepanek grabbed a quarterfinal spot opposite del Potro with a 6-2, 7-6 (7-5) decision over Albert Ramos and defending champion Bernard Tomic edged by Blaz Kavcic 6-3, 4-6, 6-4 in Wednesday's other matches.