The start of 2003 was not a good one for the Austrian, as he lost three consecutive Tour-level main-draw matches, including his Australian Open debut. He rebounded in April by reaching the semifinals, losing to then world no. 2 Andre Agassi. He also made his French Open debut, but lost to David Ferrer. At Wimbledon, Melzer upset then world no. 15 Fernando González, to earn his first Wimbledon victory, but lost to Jonas Björkman in four sets the following round. Melzer reached his first ATP Tour final at the Hall of Fame Tennis Championships without defeating a player in the top 100, but lost to Robby Ginepri in the final. In the 2003 US Open, Melzer reached the second round again, but lost Juan Carlos Ferrero. Before the end of the year, Melzer earned another top-20 victory over Tommy Robredo in the 2003 CA Tennis Trophy.