Pressel overcame soggy conditions at Locust Hill Country Club to put herself in position for her first victory since 2008, finishing two rounds at 6-under-par 138.
Top-ranked Inbee Park charged into contention with a 4-under 68, pulling into a second-place tie with first-round leader Chella Choi (73), who won the season's first major -- the Kraft Nabisco Championship -- in April.
The competitors face 36 holes of golf Sunday, with both the third and fourth rounds scheduled to be held after Thursday's rain-out.
Gal Gadot cast as Wonder Woman for 'Batman vs. Superman'
Texas principal bans speaking Spanish, stirs controversy