Croatian Davis Cup Team debut and at the 2000 Summer Olympic Games in doubles. At first, Ančić mostly played Futures and Davis Cup tournaments, winning one title in Zagreb; and from August 2001 he started to play Challenger tournaments, winning four in singles and one in doubles. He compiled a record of 30–16 in Challenger play in 2002. ATP Tour career (2002–2005) His ATP debut was at Miami Masters, where he drew a wild card, but he lost in the opening round. The highlight of his Grand Slam debut at the 2002 Wimbledon Championships was the major upset of his first round defeat of Roger Federer, the seventh seed, 6–3, 7–6(2), 6–3 in just under two hours. He finished the 2002 season in the top 100 in singles. At the ATP Indesit Milano Indoor in February 2004, Ančić made it into his first singles ATP final, defeating sixth seed Rafael Nadal and third seed Tommy Robredo. At the 2004 Wimbledon Championships, Ančić had his best Grand Slam result, reaching the semi-finals. In reaching the Grand Slam semi-finals, he jumped 36 places on the ATP singles ranking to No. 27. In doubles, he teamed up with Ivan Ljubičić, and represented Croatia at the 2004 Summer Olympics. They won a bronze medal, losing to González and Nicolás Massú in the semi-final. He won his first ATP singles title at the Ordina Open. His 2005 highlights also include the final at the Japan Open Tennis Championships, losing to Wesley Moodie. Career apex (2006) Ančić started on the 2006 ATP Tour with strong note in his second tournament of the year in Auckland, where he defeated top seed Fernando González on his way to the final. In February, he also reached the final in Marseille, losing to Arnaud Clément. He made in the quarter-finals at two Masters and two Grand Slams tournaments. Ančić was defeated by David Nalbandian at Miami and Rome and by Roger Federer at the French Open and Wimbledon. He also reached his career high at Master Series event, reaching the semi-finals at Hamburg Masters. Ančić successfully defended his 2005 title at 's-Hertogenbosch. After Wimbledon, Ančić reached No. 7, his career high in singles. At the 2006 French Open, he had a shoving incident with Paul Capdeville at the end of his second-round match. Ančić was bothered by the Chilean's repeated complaints to the chair umpire, including just before the post-match