National golfer Koh Sock Hwee overcame a four-shot deficit on Thursday to leapfrog overnight leader Sarah Tan and claim the host qualifier spot at the 2015 HSBC Women's Champions.

The 25-year-old fired a one-over 73 at the Sentosa Golf Club (SGC) for a two-day total of 154. She finished two strokes ahead of professional Christabel Goh, who closed with a 74 at the Serapong course. Sarah, 16, shot 83 and finished joint-fourth on 160.

This will be Koh's second appearance at the US$1.4 million (S$1.89 million) tournament, which is sanctioned by the Ladies Professional Golf Association Tour.

She competed in the 2012 edition, which was staged at Tanah Merah Country Club's Garden course. She posted scores of 82-86-78-79 for a 37-over total of 325 to finish last in the elite 63-women field that year.

Said Koh: "My game is a bit more mature now and I also have more variety in my shots compared to back then. This is a tough course and today, I felt that even being four shots behind I still had a chance.

"I just tried not to put too much pressure on myself and luckily I was able to make some putts on the back nine."

The Republic's top-ranked female amateur on No. 249, Koh is expected to lead the charge at the SEA Games in June, which will also be held at the same course in SGC. It will be her last tournament as an amateur before she joins the professional ranks.

This year's HSBC Women's Champions from March 5-8 will once again feature some of the game's top female golfers, including the top six in the world rankings that include Park Inbee (1), Lydia Ko (2), Stacy Lewis (3), Feng Shanshan (4), Suzann Pettersen (5) and Michelle Wie (6). Last year's winner, American Paula Creamer (20), will also return to defend her title.