Ana Ivanovic defeated Caroline Wozniacki 6-3, 6-2 to ensure there will be a new champion at the WTA Indian Wells tournament.
Wozniacki was comprehensively outplayed by the Serbian as her reign as champion ended in meek fashion.
A delighted Ivanovic, the 2008 French Open champion, said: "I was really looking for opportunities, and trying to come in as well whenever I had chance and trying to step in from both sides and trying to stay calm in my serve and execute the way I was executing in practice. I really managed to do that well."
Wozniacki's loss ensured she will drop out of the No 4 spot in next week's rankings, while keeping the tournament without a back-to-back women's winner since Martina Navratilova in 1990-91.
"She just went on a roll. She started to hit the ball harder and it was going in," Wozniacki said. "I stepped back a little bit, and it gave her the time to do what she wanted."
In the men's ATP tournament at the same venue, Roger Federer had to come from behind to beat Canada's Milos Raonic 6-7, 6-2, 6-4 in the third round of the ATP Indian Wells tournament on Tuesday.
The 30-year-old Swiss, who won three straight Indian Wells titles from 2004-2006, came into the California desert in strong form following back-to-back wins in Rotterdam and Dubai. But facing the 21-year-old Raonic for the first time, Federer fell a set behind as he struggled to adjust to the hard-serving Canadian's game.
"It was a difficult match," Federer said. "I have never played him before. He has probably seen me play a whole lot on TV which helps him out a bit." Federer hammered 10 aces, won 88 per cent of his first-serve points and saved three out of three break points in the two hour, seven minute match, but was made to work for his win.
Rafael Nadal, the No 2 seed, also progressed to the quarter-finals, beating Spanish compatriot Marcel Gronollers 6-1, 6-4, but fifth-seeded David Ferrer lost for just the second time this year, 6-4, 6-3 to Denis Istomin of Uzbekistan.