second player after Charlie Pasarell, to defeat the defending Wimbledon men's singles champion in the first round. He finished the 2003 year in the top 100 and as the Croatian No. 3, behind Ivan Ljubičić and Mario Ančić. He also averaged an ATP-best of 17.6 aces per match. He continued his success during the 2004 season, winning at Calabasas, California. He reached the round of sixteen in several tournaments, including Wimbledon. 2005: First ATP final In 2005, Karlović reached his first ATP final at the Queen's Club Championships, defeating Lleyton Hewitt and Thomas Johansson along the way. In the final he lost to Andy Roddick. There were no breaks of serve in the match. Afterwards, Roddick said Karlović's serve is "probably the biggest weapon in tennis... you don't really get a feel for it unless you are on the other side. It was not fun at times." At the 2005 US Open, Karlović lost to eventual runner-up Andre Agassi in three tiebreakers. On 19 October 2005, he finally defeated Roddick in the Madrid Masters event. In November 2005, he was a member of the Croatian team that won the Davis Cup. He did not play in the finals, but played in a semifinal dead rubber. 2006: Breaking into the top 50 in singles and doubles On 26 February 2006, he won his first ATP Doubles Tournament with South African Chris Haggard, beating James Blake and Mardy Fish in the 2006 Regions Morgan Keegan Championships and the Cellular South Cup, Memphis, USA. On 27 February, he reached a career high of No. 47 in doubles and on 8 May he also reached the top 50 in singles. 2007: First ATP title and breaking top 30 Karlović and Roger Federer were the only players who won titles on three different surfaces during the 2007 season. At age 28, he won his first ATP singles title at the 2007 U.S. Men's Clay Court Championships in Houston, Texas, defeating Mariano Zabaleta in the final. On 29 May 2007 at the French Open, he defeated eighth seed James Blake in the first round. In the next round he lost to Jonas Björkman in five sets. On 23 June 2007, he won his second title of the year and his career at Nottingham, the last grass tune-up before Wimbledon, defeating seventh seed Stanislas Wawrinka, Gilles Simon, Juan Martín del Potro, second seed Dmitry Tursunov (a match