Heavy rainfall resulted in the suspension of second-round action at the $3.25 million (24.34 million kronor) championship, the biggest event in women’s golf.
Gustafson birdied the first hole, her only hole on Friday, to move in front at even-par at the Oakmont Country Club course.
The world’s top player, Cristie Kerr of the US, shot an even-par 71 on Friday and moved into a tie for second at one-over 143.
“We had a very dry course and it can take a lot of rain,” said the USGA’s Mike Davis, who is confident that improving weather will allow the biggest event in women’s golf to finish on schedule Sunday night.
A steady string of thunderstorms that began with 100 of the 156 golfers still to begin or complete the second round caused play to be suspended at mid-afternoon on Friday. Twenty-eight of the 31 golfers who were within three strokes of the lead had played only a few holes or had yet to tee off.
Kerr finished her round before the pelting rains flooded Oakmont. Brittany Lang fell from a first-round 69 to a three-over 74 as temperatures went down but the scores didn’t, with Christina Kim a shot back at two-over 144 following back to back 72s.
The leaders won’t start the third round until about 5:30 pm local time on Saturday (11:30 pm Swedish time) and will finish on Sunday morning.