Del Potro reaches 2nd straight Vienna final

Juan Martin del Potro reached his second consecutive final at the Austrian Open on Saturday as he defeated Gilles Muller 7-6 (7/4), 7-6 (7/5) in a duel of aces. The top-seeded Argentine who lost a title bid here a year ago to Jo-Wilfried Tsonga, fired 17 aces to 16 for Luxembourg\'s Muller, who was playing his second semi of the season after Atlanta over the summer. The battle lasting just under two hours put Del Potro up against the winner from second seed Janko Tipsarevic or Slovenian qualifier Grega Zemlja. Both Del Potro and Tipsarevic are duelling for one of three - possibly four if injured Rafael Nadal does not play - vacant spots at next month\'s season-ending World Tour Finals in London. Del Potro stands provisional seventh while Tipsarevic is ninth in the points chase. Del Potro said that, while he was pleased to reach the final, he is still trying to shake the rust off of his game after a month out with a left wrist injury. \"I\"m playing but you can always play better and improve your game,\" said the 24-year-old South American, \"Being in a final means a lot for me after a month without playing. \"I\'m showing a good level, but I still need to improve.\" The match finished without a break of serve, with Del Potro disappointed not to have converted on the two he had against Muller. \"Break points were almost like set points. If you miss one you are under pressure. The difference today was that I played better in the tiebreaks.\" Del Potro now stands 7-1 in Vienna on his third appearance as he played in his eighth semi-final of the season. The Argentine will be competing in his 17th final and bidding for a 12th trophy. He has not dropped serve all week. Del Potro said that while the race to London with this weekend and another two weeks to go is important to him, he has to keep his focus strictly on what\'s immediately ahead. \"I\'m trying to qualify, but I\'m thinking only of this final. After that there is Basle, it\'s always step by step.\"