Second seed Juan Martin Del Potro lifted his game with the Davis Cup final approaching as the Argentine defeated German Philipp Petzschner 6-3, 6-4 to progress to the third round of the Austrian Open on Wednesday. A week ago Del Potro was beaten in the first round in Stockholm by James Blake, a poor start to the indoor season which will climax with the 2009 US Open winner leading his side in the Davis Cup final with Spain in Seville December 2-4. "I played much better today than the Blake match," said Del Potro, winner of nine career titles. "But I need to play better. I'm in the quarter-finals but I must lift my level. "Whomever I meet on Friday will be tough, I have to be ready to fight. I'm feeling very good but Petzschner's game is difficult for me. "I'm the taller player and he was playing a lot of drop shots and slices." Del Potro, ranked 15th as he builds on his comeback from wrist surgery in 2010, will play either German veteran Tommy Haas or Slovenian qualifier Aljaz Bedene, who advanced when Ivo Karlovic quit with a bad back in their match. The Argentine - making his first appearance here since 2008 - got an early break in the first set against Petzschner, who captured his lone ATP singles title here three years ago as a qualifier with a win over Gael Monfils. The last two games of the 43-minute set were marathons, with the German saving two Del Potro set points for 3-5. A game later, Del Potro was again pushed, forced to salvage four break points and requiring three more set points to finally take the lead. In the second, Del Potro broke for 5-4 and served out for the win a game later, ending with a spectacular reflex forehand off his shoelaces which landed good in the far corner for victory in just under 90 minutes with eight aces.