Campestre de Aguascalientes by defeating the likes of Dick Norman and Thiago Alves, before beating Sergio Roitman in the final. Del Potro qualified for the main draw of his first Grand Slam in the 2006 French Open at the age of 17. He lost in the opening round to former French Open champion and 24th seed Juan Carlos Ferrero. Having received a wild card, he reached the quarterfinals of the ATP event in Umag, Croatia, where he lost in three sets to the eventual champion, Stanislas Wawrinka. In Spain, he participated in the Open Castilla y León Challenger tournament held in Segovia, defeating top seed Fernando Verdasco in the quarterfinals and Benjamin Becker in the final. Del Potro qualified for his first US Open in 2006, after being seeded ninth in the qualifying stages, where he beat Brian Vahaly, Wayne Arthurs, and Daniel Köllerer in straight sets. In the US Open, he lost in the first round to fellow qualifier Alejandro Falla of Colombia in four sets. He went on to qualify for his first ATP Masters Series tournament in Spain, the Mutua Madrileña Madrid Open, where he lost in the first round to Joachim Johansson. After receiving a wild card thanks to Roger Federer, he reached the quarterfinals of the 2006 Davidoff Swiss Indoors in Basel, Switzerland; defeating lucky loser Tobias Clemens in the first round and George Bastl in the second round, before losing to the eventual runner-up Fernando González in three sets. Del Potro finished 2006 as the youngest player in the top 100 at 18 years, 2 months. 2007: Top 50, Davis Cup quarterfinal Del Potro began the year by reaching his first semifinal in ATP Adelaide, Australia, where he lost to Chris Guccione, having beaten Igor Kunitsyn earlier in the day. He then reached the second round of the Australian Open, where he had to retire because of injury in his match against eventual finalist Fernando González in the fifth set. In February, del Potro played for Argentina in the first round of the Davis Cup against Austria, winning the fourth and deciding match against Jürgen Melzer in five sets, allowing Argentina to qualify for the quarterfinals. Del Potro defeated Feliciano López before losing to eventual semifinalist Mardy Fish in the second round of the indoor Regions Morgan Keegan Championships. In his next ATP Masters event, he reached the second round of the Pacific Life