Serena Williams helped her sister Venus stay on top of the world rankings by beating Jennifer Capriati in the final of the State Farm Women's Classic.

Serena triumphed 6-2 4-6 6-4 to end Capriati's hopes of going back to the top of the tree.

It was Williams' first appearance since she sustained an ankle injury in Sydney in early January.

Serena looked superb in the first set, and raced into a 5-0 lead en route to taking the set 6-2.

Capriati, unbeaten in 11 matches heading into the final, hit back strongly to take the second set 6-4. The crucial break came in the 10th game.

The final set was a tense affair, with the crucial moment coming in the third game.

Capriati double-faulted three games to hand Williams a vital break and a 2-1 lead.

In the final set, Capriati double-faulted three times in the pivotal third game, including on break point to send Williams to a 2-1 lead.