In July, he played two singles matches for Argentina against Russia in the Davis Cup at the Olympic Stadium in Moscow. He defeated Nikolay Davydenko, 6–4, 7–6, 7–6, in the first rubber, and Mikhail Youzhny, 7–6, 6–4, 6–3, in the fifth and final rubber, giving Argentina a victory of 3–2 to qualify for the semifinals. He made his return in the 2010 Legg Mason Tennis Classic, where he won the title, his first since 2009 Medibank International Sydney after wins over Rajeev Ram, 6–4, 6–0, Stanislas Wawrinka, 6–3, 6–1, Marco Chiudinelli, 6–1, 6–0, Gilles Simon, 3–6, 6–2, 6–3, and Marin Čilić, 6–2, 6–2. He defeated Marcos Baghdatis in the finals, 6–2, 7–6, guaranteeing a jump in the rankings up to the vicinity of world no. 45. The following week, he had a successful run to the quarterfinals in the Roger's Masters Series in Toronto, defeating David Ferrer, Tommy Robredo, and Robin Söderling, before losing to World No. 4 Andy Murray after this 11-match winning streak. This run took his rank up to world No. 37. He competed at the 2010 BNP Paribas Masters, where he lost again to Murray, 6–2, 4–6, 3–6, in the second round.