Mi Hyun Kim notched the round of the day with a 4-under 68 to move into a tie for third at even-par 144. Kim is joined there by overnight leader Lorie Kane, who stumbled to a 2-over 74.
Rosie Jones and Beth Daniel each carded rounds of 2-under 70 to share fifth place at 1-over-par 145.
Delasin opened with a birdie on the par-5 fourth at Magnolia Grove Crossings Course to move to 1 under. She stumbled to bogeys on the sixth and eighth to head to the back nine at 1 over.
On the back side, Delasin stumbled to another bogey on No. 11, but caught fire from there. She dropped her tee shot to the par-3 14th inside four feet to set up birdie.
Her lengthy eagle putt on the par-5 16th came up just short, but she tapped in for birdie to get back to even par. Delasin knocked her tee ball within five feet at the 17th for another birdie and a share of the overnight lead.
'I've just been trying to get the right distance because these greens are so firm,' said Delasin. 'I am an aggressive player by nature and if my caddie weren't here with me, I'd be attacking every pin and going over every green. I'm lucky he is here with me this week holding me back a bit and helping me play smart.'
Delasin has a chance to climb into the top 30 on the money list, which would qualify her for next week's season-ending ADT Championship, but knows there is plenty of golf left this weekend.
'Next week is in the back of my head, I really want to play next week, but I'm in contention and I haven't been in contention in a while,' Delasin said. 'So I'm just going to go out and play a solid round tomorrow.'
Han, unlike Delasin, made her move on the front nine. She opened with a birdie at the third and made it two in row with a birdie on No. 4. However, she struggled to a bogey at the fifth.
A birdie on the sixth helped Han make the turn at minus-2. The back nine was not kind to Han though.
The South Korean, who has two wins and 10 top-10s this year, dropped shots on the 10th and 12th to fall back to even par. She righted the ship with a birdie at the 17th for a share of first place.
'My putting was pretty good but my driving was not so good,' said Han. 'Putting is pretty tough and yesterday the wind was pretty tough, but not today.'
Karrie Webb, who entered the day in second place, holed out from the fairway on No. 18 for eagle, but it was only good enough to give her a round of 3-over 75. She shares seventh place with Rachel Teske, Meg Mallon, Wendy Ward and Laura Davies at 2-over-par 146.
Grace Park and Candie Kung are one stroke further back at 3-over-par 147. Betsy King rebounded from an opening 79 with a 3-under 69. She is at 4-over-par 148 tied with Gloria Park.