the winners circle. Del Potro's next tournament was the ATP Masters at the 2011 BNP Paribas Open. He reached the semifinals, where he lost to top seeded Rafael Nadal in straight sets. Del Potro then flew to Key Biscayne, Miami to participate in the second ATP Masters of the year at the 2011 Sony Ericsson Open. Del Potro made it to the fourth round, in the third round he defeated world No. 4 Robin Söderling in straight sets, however in the next round he lost to eventual semifinalist Mardy Fish in straight sets. He then played in 2011 Estoril Open, which was del Potro's first tournament on clay since he lost the 2009 Roland Garros semifinal to the eventual champion Roger Federer. In Estoril, he defeated Fernando Verdasco in the final. On the way to the final, del Potro defeated top seeded Robin Söderling (Who was two time-finalist in the French Open) and dropped just one set in his five matches. After suffering an 8-millimeter tear in his left rectus, del Potro withdrew from 2011 Mutua Madrid Open and did not participate in the 2011 Internazionali BNL d'Italia, but confirmed that he would play the French Open. Del Potro lost to Novak Djokovic in the third round. Del Potro reached the round of 16 at Wimbledon for the first time by defeating Flavio Cipolla, Olivier Rochus, and Gilles Simon. He then lost to world No. 1 Rafael Nadal, in four sets, in the fourth round. Del Potro returned to the top 20 at world No. 19 for the first time in nearly a year. His next tournament was the Farmers Classic in Los Angeles, where he received a first-round bye as the second seed. He defeated James Blake but was defeated by Ernests Gulbis in the quarterfinals. At the 2011 Rogers Cup, seeded 16th, del Potro defeated Jarkko Nieminen before losing to Marin Čilić in the second round. At the Western & Southern Masters tournament, del Potro lost to Roger Federer, snapping the two-match winning streak he had against his rival. Del Potro entered the 2011 US Open seeded 18th. He beat Filippo Volandri and Diego Junqueira before losing to Gilles Simon in the third round, thus ending his US Open campaign. After the US Open, del Potro played in the Davis Cup semifinal against Serbia, winning both of his rubbers against Janko Tipsarević and world No. 1 Novak Djokovic.