Korda edged out fellow American Ryaan O'Toole with a birdie on the first extra hole to claim her second LPGA Tour victory of the year.

The 25-year-old also won the LPGA Drive On Championship in January in a play-off over Kiwi Lydia Ko.

Korda posted a two-under-par 69 at the Palos Verdes Golf Club on Monday (AEDT) while O'Toole's closing 66 also left her at nine-under through 72 holes.

Playing in only her third LPGA Tour event as a full-time member, Ruffels needed a birdie at the last to force a three-way play-off, but left her 20-foot attempt short.

It wasn't to be for Gabi Ruffels in California, the 23-year-old finishing in a tie for third. PHOTO: Getty Images.

The 23-year-old had held a share of the lead following three birdies in four holes heading to the 9th tee.

But a double bogey six on the par-4 9th ultimately cost Ruffels the biggest win of her career to date.

She signed for a final-round 70 to share third with American Alison Lee (70) as Korda celebrated her 10th LPGA Tour win.

Korda will return to World No.1 for the sixth time – and first time since last August – after supplanting compatriot Lilia Vu from top spot.

 – Darren Walton.