World No.1 amateur Lydia Ko has suffered another heart-breaking loss to Swedish professional Caroline Hedwall at the NSW Open on the ALPG Tour.
The record-breaking 15-year-old, who last year became the youngest winner of a professional golf event when she won the event by four shots at the age of 14, was in a share of the lead with two holes remaining as she looked to defend her title.
But the Swede, who came from behind to defeat Ko on the final hole in the 2011 championship, when Ko three-putted from 5m, delivered when it mattered most.
She made a crucial par on the par four 16th, which Ko bogeyed, for a one shot lead heading to the final 118m par three 18th. Hedwall sealed her victory with a birdie at the final hole to record a two stroke victory.
Ko, who lost in the third round of the Australian Amateur last week, will be disappointed to come up just short after a valiant effort to defend her title.
She began the final round on eight under par after rounds of 67 and 69, only one shot back, was off the early pace as she opened with bogeys on one and two.
But Ko rallied midway through the front nine as she made birdies on five and six and an eagle on seven to make the turn in two under par 34.
She was now only one back from Hedwall and had the momentum on her side heading into the final nine holes. Ko added a further birdie on the 11th to get into a share of the lead with seven holes remaining.
The US Amateur Champion added another birdie on the 14th to get to 12 under par which Hedwall, who had made three birdies and a bogey on the front nine, matched and the pair remained all tied up with four holes to play.
The pair traded pars on 15 and 16 and then Ko's dropped shot on the 17th handed the professional the advantage and she added an exclamation mark to her win with a fine two on the last.
Fellow Amateur Minjee Lee of Australia carded a one under par 71 to finish third on a 10 under par total three shots back from Hedwall.
New Zealand professionals Caroline Bon, Cathryn Bristow and Lynnette Brooky finished in a share of 17th place, Marnie McGuire was tied 54th and Phillis Meti was tied 58th.
Ko will now head to the Volvik RACV Ladies Masters in Queensland this week ahead of the NZ Women's Open hosted by Christchurch at the Clearwater Golf Club from February 8 - 10.