VIENNA (AP)— Top-seeded Juan Martin del Potro and qualifier Grega Zemlja advanced to the final of the Erste Bank Open on Saturday. Del Potro, a runner-up last year, defeated Gilles Muller of Luxembourg 7-6 (4), 7-6 (5) to reach his fourth final of the year, while Zemlja rallied to stun second-seeded Janko Tipsarevic 3-6, 7-6 (5), 6-2 for his first career final. The 70th-ranked Zemlja was 0-4 against top-10 players.