Lauren Walsh finished in a tie for 31st as China's Ruixin Liu delighted the home fans with a three-stroke victory at Mission Hills China.
The Dubliner had battled on Friday to make the cut with a bogey-free round extending her tournament, but she had to be content with a closing round of 73 on a day when low scoring was rare.
No such issues for the 26-year-old champion who had started one shot behind overnight leader Trichat Cheenglab of Thailand.
Liu made her first birdie on the sixth hole before adding another on the 11th to put her into the lead on the World Cup Course.
An eagle on 16 put her two shots ahead and she finished in style with a birdie at the last for her round of 68 to seal her maiden Ladies European Tour title.
"I wasn't very nervous today at all, I was just trying to play my golf because it's very hot today," she said.
"It's so sweet, to have friends come over and watch me and to have my dad on the bag as well. The crowd is amazing so thank you."
The victory was even sweeter for Liu who lives on site at Mission Hills China and it was the first time she has played in a professional event in Shenzhen since turning professional in 2017.
Four players finished in a share of second place with Switzerland’s Chiara Tamburlini, Thailand’s Cheenglab and Chinese duo Liqi Zeng and Qianhui Lin all on 13-under par.
Sweden’s Kajsa Arwefjäll and China’s Ruoning Yin finished in a tie for sixth place with South Africa’s Casandra Alexander, China’s Ying Xu and Sweden’s Moa Folke ended in a share of eighth place.
Ireland's Amy Foster failed to make the cut.
The LET will now take a two-week break before the season-ending Andalucía Costa del Sol presented by Oysho at Real Guadalhorce Club de Golf from 27-30 November.
