A day before turning 40, Japan's Kimiko Date Krumm bundled defending champion Maria Sharapova out of the Pan Pacific Tennis Open in the first round.
Date Krumm produced a shock 7-5 3-6 6-3 victory over Russia's former world number one, who squandered three points for a 4-2 lead in the final set.
Sharapova broke to take a 3-2 lead in the final set but buckled when up 40-0 in the next game, double-faulting twice en route to surrendering her own serve.
The Russian, who committed 11 double-faults in total, praised the fitness of her opponent, who returned to professional tennis in 2008 after 12 years away from the game.
Seven of the world's top 10 women's players are competing in Tokyo this week at the $NZ 2.7 million tournament.