Bedminster, New Jersey (AFP) - China's Feng Shanshan birdied the last hole after 17 consecutive pars to seize a one-stroke lead after Saturday's third round of the US Women's Open with US President Donald Trump in attendance.

The 27-year-old Rio Olympic bronze medallist missed her only fairway of the day at the par-five 18th, sending her tee shot into the deep left rough.

But she blasted out into the fairway, dropped her approach three feet from the cup then sank the putt to finish one-under 71.

That left her on nine-under 207 after 54 holes at Trump National, with Trump among those watching her in the third major championship of the LPGA season.

"I was trying so hard to make putts," she said. "My putting was really working for the first two days. Today my speed was not as good. My Plan A wasn't working so it was Plan B which is hit the ball closer to the hole.

"At 18. I hit it really close and finally made a birdie. Made my day."

South Koreans held the next six spots on the leaderboard, with 17-year-old world amateur No. 2 Choi Hye Jin and Amy Yang sharing second on 208 after third-round 70s.

Park Sung Hyun (67) was fourth on 210 with world No. 1 Ryu So Yeon (71), Lee Mi Rim (67) and Lee Jeong Eun (73) all on 211.

Feng could become the first US Women's Open wire-to-wire winner since American Hollis Stacy in 1977.