Seeded 13th and aged 17 at Wimbledon, she reached her first Grand Slam semifinal by defeating Ai Sugiyama. There, she defeated fifth seed and former champion Lindsay Davenport. In the final, Sharapova upset top seed and defending champion Serena Williams to win her first Grand Slam singles title, and become the third-youngest woman to win the Wimbledon title, behind only Lottie Dod and Martina Hingis.
Sharapova also became the second Russian woman (after Anastasia Myskina had won the year's previous major at Roland Garros) to win a Grand Slam singles title. The victory was hailed by the media as "the most stunning upset in memory", with other writers commenting on her arrival as a serious challenger to the Williams' dominance at Wimbledon.
She entered the top 10 in the rankings for the first time as a result of the win. Following her Wimbledon win, attention and interest in Sharapova in the media greatly increased, a rise in popularity dubbed as "Maria Mania".
However, on court, she was struggling to achieve results, winning just three of six matches in her preparations for the US Open. At the US Open itself, she reached the third round, before being eliminated by Mary Pierce. In order to regain confidence, Sharapova played and won consecutive titles in Asia in the fall, the Hansol Korea Open Tennis Championships and the Japan Open Tennis Championships.
In October, Sharapova defeated Venus Williams en route to making the final of a Tier I event for the first time at the Zurich Open, losing in the final to Alicia Molik. She then made her debut at the year-ending WTA Tour Championships. There, she won two of her three round-robin matches (including a win over US Open champion Svetlana Kuznetsova) in order to advance to the semifinals, where she defeated Myskina. In the final, she defeated Serena Williams, after trailing 4–0 in the final set.