Her 67 followed rounds of 66 and 67 earlier in the weekend and will all count towards the Vare Trophy, awarded to the player with the lowest average score of the season. Ko sat in second place going into the tournament, behind Australia's Minjee Lee, but will certainly close the gap after her rival fired scores of 71 and 69.
Ko won the Vare Trophy in 2021 with an average score of 69.329.
Finally, Daniel Hillier finished the European Challenge Tour's Swiss Challenge with a sensational round of eight-under to win the tournament, his second tour win of the season.
Hillier carded ten birdies and two bogeys to come back from four shots behind the third-round leader and move closer to securing a fulltime card on the DP World Tour in 2023.
With four events left on the Challenge Tour, Hillier sits in 13th place overall and needs to remain inside the top 20 to secure a DP World Tour card.
"That was pretty unbelievable," Hillier told media following the win.
"It was a crazy day and I felt like I was in autopilot. I've been working on my short game a lot in the last couple of years and it's something that has really let me down in the past. To be able to hole those putts under pressure today just shows I am doing some of the right things and now I just need to keep my head down and hope the wins keep coming.
"This is massive for me being towards the end of the season. I've moved inside the top 20 and now I'm in a strong position to get my DP World Tour card for next season. The jobs not done yet so I need to play as well as I can for the final few events."