Del Potro seals London spot

Juan Martin del Potro secured his place in the ATP World Tour Finals on Thursday after Rafael Nadal\'s injury-enforced withdrawal from the eight-man season-ender opened up another vacancy. The Argentine, who had already increased his qualification hopes for London by winning the Vienna title last weekend, was delighted to make it into the finals for the third time. But he was also sympathetic to the plight of Nadal who had to pull out of the London showpiece, which begins a week from Monday, as he continues to battle back from the knee injury which has kept him off tour since June. Del Potro said he knows exactly how Nadal feels after his own wrist injury absence in 2010 saw his career suffer a worrying setback. \"I\'m sad for Rafa, he\'s really trying in his comeback. But it\'s not easy after such a long time away. I had the same feeling with my wrist,\" said del Potro, who made the Swiss Indoors quarter-finals Thursday with a 7-5, 6-1 defeat of American Brian Baker. \"We miss Rafa a lot on the Tour. He is one of the best players in history, he will come back strong. \"I\'m sure it will be very soon. He will be ready to win a big event again, I know that he can play better than me when he makes his comeback, I wish all the best to him.\" On reaching the World Tour Finals, del Potro, the 2009 US Open champion, added: \"For me it\'s a gift for my effort during the year. \"It\'s only eight players fighting for one tournament. It\'s the best eight players of the year, so it\'s very important to me. I\'m so glad to be there once again. I will be fighting against the big names and maybe I\'ll have a chance to make another final.\" Roger Federer, Novak Djokovic, Andy Murray, David Ferrer and Tomas Berdych have already booked their places in London, leaving just two singles berths up for grabs. Jo-Wilfried Tsonga, Janko Tipsarevic, Richard Gasquet and Nicolas Almagro are among those in contention for the last two places. Elsewhere in the second round at the St Jakobshalle, where hometown star Roger Federer is bidding for his sixth title from seven editions, Russian sixth seed Mikhail Youzhny defeated Australian Matthew Ebden 6-3, 6-1. Two Frenchmen also celebrated wins, with Paul-Henri Mathieu overcoming Russian veteran Nikolay Davydenko 6-3, 6-7 (2/7), 6-4 and Benoit Paire lining up a Friday quarter-final date with Federer through his defeat of Lukasz Kubot 6-4, 6-4. The 23-year-old Paire is buoyed by being at his highest ranking of 46 and fresh from an upset of fifth seed Andreas Seppi in the first round. Paire nudged his 2012 record to 25 wins against 24 losses as he took down Kubot. The Frenchman overcame the Pole in just under 90 minutes with six aces and three breaks of serve. \"It\'s great to be in a quarter-final and to be playing Roger Federer,\" added the Frenchman. \"I had a good match against Kubot which gives me confidence. And of course beating Seppi may have been a surprise. \"Federer had a tough time playing (Thomaz) Bellucci in the second round, it went to three sets. Anything is possible in tennis and I have my chances if things go well for me.\"