American amateur Jenny Chuasiriporn made a 30-foot putt for a birdie on the final hole at Blackwolf Run in Kohler, Wisconsin to force an 18-hole play-off against South Korean Se Ri Pak in the US Women's Open last night.

Chuasiriporn's 72 tied her with third-round leader Pak, who shot a 76 as the two finished at sixover. Pak missed from six feet on the last which would have sealed the victory.

Mhairi McKay of Scotland was the top finisher from Britain. She entered the day just one over but played her final round in 78 to end up nine over par and tied for seventh place.