The 21-year-old is Australia’s highest ranked player and showed her class in the final round at Trump National Bedminster in New Jersey with five birdies in her final seven holes to rocket up the standings.
Lee was the only Australian to finish in red figures, her 6-under 66 moving her from 2-over for the week to 4-under and T11.
After a 77 on Saturday to fall out of contention, Lee was steady over her opening nine holes in the final round to go to the turn 2-under.
A bogey at 10 might have killed her momentum but instead it seemed to spark something in the Western Australian who parred the 11th before lighting up the final holes.
“Well, I didn't have a very good day yesterday, so it's 100 per cent better,” Lee said of her weekend play.
“I mean, overall I had a pretty good week. We take the 5-over out (Saturday’s round), it would have been a great week.”
Lee said the key to the final round was to tee off with no goals in mind.
“I didn't have any expectations,” she said when asked if her play Saturday had motivated her Sunday.
“I just came out and thought let's just finish with a good day at a U.S. Open.”
The result is Lee’s best in the richest women’s tournament in the world and has her confident ahead of the final two majors of the year.
“I don't think I'm going to change anything. Obviously, I am hitting it good and I am putting it good,” she said of her plans for the rest of the season.
“I mean, we have the British Open and the Evian, two majors left. Hopefully I can have good results there. I mean, I'm just going to do the same and hope for the best.”
While Lee had positives to take from her week, there was mostly disappointment for the rest of the Australian contingent.
Karrie Webb was next best of the four who made the cut, the two-time winner finishing with a 4-over 76 to be 6-over for the week and T44.
Webb has missed only three cuts in her 22 US Women’s Open starts and, while not a contender in 2017, added to her legacy as Australia’s best female player.
Katherine Kirk faded with a final round 78 to finish 7-over and T48 while Su Oh endured three double bogeys on her way to a 77 and T56 at 10-over.
SUNG HYUN PARK WINS 2017 US WOMEN'S OPEN