"Winning would be great, but I'm just going to take it day by day," Ko told the LPGA Tour before the tournament.
"If it goes my way, great, and then I become world No 1, it's even better. But I'm not going to think about it. I'm just going to try and enjoy it and try to think of it as a normal, another LPGA event."
The tournament is intriguingly poised at the mid-way stage given the big names who are near the top of the leaderboard.
Meanwhile, Kiwi Danny Lee has missed the cut at the Wyndham Championship in North Carolina on the PGA Tour by five shots after rounds of 73 and 70.
Lee, who should retain his PGA Tour card for next season, was projected to drop six places to 115th on the FedEx Cup standings.
The top 125 players on tour retain their card for next season and there's four more tournaments left in the 2013-2014 campaign.
Manawatu's Tim Wilkinson, who has 107th on the FedEx Cup standings before this weekend, skipped the tournament in North Carolina.