Frenchwoman Bartoli was beaten by Williams for the All England club final two years ago.

Bartoli's bitter memory was still fresh as she struck back in the three-set thriller lasting two and three-quarters hours in northern California on Sunday.

"It was great to play Venus again," said the Frenchwoman, "I have a lot of good memories from Wimbledon."

Bartoli lost the title match here a year ago to Canadian Aleksandra Wozniak. She was unable to beat Williams in straight sets while leading a set and 5-4, failing to serve out the victory.

Bartoli will move up two spots in the rankings to 12th after claiming her second title of 2009 and the fifth of her career.

Williams, 29, had a strong history at Stanford, playing her seventh final in eight visits.

"I had a great tournament," said the disappointed American. "But Marion was just too good."

She won her only two titles at the start of the decade in 2000 and 2005, last finishing runner-up to Kim Clijsters in 2005. The five-time Wimbledon champion will remain on third in the world behind number one Dinara Safina of Russia and sister Serena Williams.

Bartoli went up an early break in the opening set only to lose it a game later. But the French player took the lead again on a third consecutive break and added an insurance policy with another for 5-2 before closing it out in 40 minutes.

The unseeded Bartoli jumped out to a 1-0 start in the second with another break of the erratic Williams. But serving for victory, Bartoli's level dropped, saving two break points but missing on a third as her opponent levelled at five games apiece.

Williams saved break points in the next game, 6-5, with Bartoli succumbing to a double-fault to hand over the set 7-5.

The third set also began Bartoli's way with a break, which she promptly lost for three-all. But a re-break in the seventh game finally put the Frenchwoman on the right path, with Bartoli serving out the win on her first match point after coming form love-30 down in the final game.