Stephanie Meadow secured the sixth top 10 finish of her career after an impressive closing 70 at the JTBC Classic in California, where Atthaya Thitikul defeated Denmark's Nanna Koerstz Madsen on the second play-off hole to win her first LPGA Tour title.

The Antrim golfer ended on ten-under-par, six strokes off Madsen and Thitikul, who fired an eight-under-par 64 to force the play-off with the lowest round at Aviara Golf Club all week.

Meadow made a blistering start to her round and was out in 33 after birdies at three, four, seven and eight with a bogey at the par-three sixth doing little to disrupt her rhythm.

Something special was needed to get within the leaders on the back nine, but a return of eight pars and a bogey saw her finish in a tie for 10th with South Korea's Amy Yang.

A disappointing front nine ruled out any chance of Leona Maguire making a Sunday run as she finished on four under after a closing 74.

The Cavan golfer started her round in ideal fashion as a birdie at the first moved her to seven under, but she would give that shot away at the next hole.

Another birdie followed on three but double-bogeys at the fifth and eight stalled her progress with some of the damage repaired with a birdie on the ninth.

One more birdie followed at the 14th after a run of four pars but a closing bogey saw Maguire finish just inside the top 50.

Atthaya Thitikul holds the winners trophy

At the top of the leaderboard, Madsen entered Sunday with a three-stroke lead but only managed a two-under 70.

Her birdie at the par-5 17th hole moved her into sole possession of the lead at 17-under, but she bogeyed the last to fall back into a tie with Thitikul.

They replayed No. 18 twice. After both parred the first time through, Madsen's second shot on the second play-off hole found the water, leading her to a double bogey.

Thitikul tapped in a short bogey putt to win, the 19-year-old becoming the youngest winner on tour since Canadian star Brooke Henderson won the 2016 Cambria Portland Classic as an 18-year-old.

"Anyone (who comes) here, they want to win," Thitikul said.

"I want to win, but didn't expect (it would) come really fast, in my rookie year as well. It's just crazy in my mind right now. I cannot believe that I became an LPGA winner."