Victoria Azarenka thrashed world number one Serena Williams 6-3 6-1 to win the Sony Ericsson Open title in Miami.
The 19-year-old Belarusian thwarted Williams' bid for a record sixth title in the event with a comprehensive 71-minute defeat - although the top seed was hampered by injury.
Williams had strapping on her left thigh and struggled to move fluidly throughout the match, although some erratic ground stroke also did not help her cause.
The American was 3-2 ahead before Azarenka took charge with five games on the spin, and she then took the final five game after Williams won her solitary game of the second set.
Azarenka was clever in pushing Williams wide at every opportunity to test out her injured thigh, and the move paid off with her third title of the y ear following wins in Brisbane and Tennessee.
"I've improved almost everything since last year but most of all I am believing in myself a little more, believing I can win tournaments," said the Arizona-based Azarenka.
Williams was clearly not 100 percent fit but refused to use that as an excuse for her defeat.
"I'm not one to make excuses, I just want to give Victoria credit today, that's all I can say," she said at the award ceremony.
"I think she has really, really improved. I actually look forward to playing her again so I can play a little better and obviously do better.
"But I think she obviously has potential and she's going to be a really good player."
For 11th seed Azarenka, the victory will take her into the top ten in the world rankings at a career-best number eight in the standings.