Casablanca and Stuttgart. He also emerged as a more potent force at the Grand Slams as he reached his first quarterfinal at the French. Doping On August 8, 2005, Cañas was suspended for two years and was forced to forfeit $276,070 in prizes by the ATP after testing positive for a diuretic called hydrochlorothiazide, a substance with no benefits in itself other than as a treatment for hypertension, but used to cover other forbidden substances. No traces of any other forbidden substance were found in Cañas's sample, and the player asserts the diuretic was present in some medicine prescribed by ATP doctors Mercader and Chinchilla for a cold he contracted during the Acapulco tournament in Mexico. Just a few weeks before his ban started, Cañas had been at the highest ranking of his career, world number eight. Cañas vowed to fight the ban, claiming he was innocent of the charges against him. Cañas took his case to the Court of Arbitration for Sport. His perseverance paid off on May 23, 2006, when he was acquitted of deliberate performance enhancement through illegal substances because the substances were in a prescription medicine. He was, however, considered careless in not checking the medicine before ingesting it. He was allowed to return to full professional activity from September 11, 2006, and the money prizes acquired before the suspension was restored. His points, which determine a player's ranking, were nil upon his return, having expired. Return Upon his return to the tour, Cañas won five Challenger titles and one ATP title (2007 Brasil Open). In the six months after his return, he had won 42 of 47 matches, going from being unranked to rank 60. He won his first ATP-level match since his September return on February 15, 2007, beating Marcos Daniel 6–1, 6–4. On March 11, 2007, Cañas defeated ATP ranked number one Roger Federer 7–5, 6–2 at the Indian Wells Masters, ending Federer's streak of 41 consecutive victories, 5 short of Guillermo Vilas's record on ATP Tour matches. He defeated Federer again (7–6, 2–6, 7–6) 16 days later at the Miami Masters to back-up his victory at Indian Wells. This double victory made him the only player (besides Rafael Nadal) to have defeated Federer in consecutive tournaments since 2003. Cañas told the New York Times that "I came back very motivated, I came back with a lot of energy." Cañas became the first