This is the first time in the championship’s 30-year history that the top two seeds will meet for the Mildred Prunaret Trophy. Thursday’s winner will also join Carol Semple Thompson (1990), Ellen Port (2000), Potter (2013) and Margaret Shirley-Starosto (2014) as the fifth medalist to win the championship.

Johnson, 33, of Norton, Mass., never trailed in her 6-and-5 quarterfinal victory over three-time finalist and No. 8 seed Shirley-Starosto, 30, of Woodstock, Ga. But her 1-up semifinal victory over Olivia Herrick, 28, of Roseville, Minn., was a different story. Johnson’s bogeys at the par-4 seventh and 10th holes provided No. 13-seeded Herrick with a 2-up lead – and gave Johnson her first deficit of the entire championship.

“At some point I knew I was going to get down coming into match play,” said Johnson, a sales representative for Ping. “I like this back side and knew that there was some holes coming up that I could definitely win if I made par, so that was kind of my mindset when I made the turn.”

And make par, she did. Johnson got up and down for a winning par at No. 11, and squared the match with another par when Herrick missed a short par putt at No. 12.

The match turned at the par-4 17th, with both players finding difficult lies in the left greenside rough. Herrick sent her pitch well past the hole, and Johnson deftly guided her chip from 20 feet in close. Herrick could not make the comebacker, and Johnson took a decisive 1-up lead.

“(When) she hit hers over, it freed me up a little bit not to necessarily be a little more aggressive but just to kind of do my thing and get it close,” said Johnson. “It was an awesome, awesome chip.”

Despite the loss, Herrick took nothing but positives from her experiences at Kahkwa, where she notched the best showing of her 10 USGA championship starts.

“If you would have told me last Wednesday that I was going to be standing here right now having just lost to Shannon, I would have been just fine with it,” said Herrick, a graphic designer who sits on the board of directors for the Minnesota Golf Association. “I'm going to try to look at the positives.”

Like Johnson, Potter, 28, of Indianapolis, Ind., reached the championship final by winning two very different matches on Wednesday. Potter, the 2013 champion and 2014 runner-up, barely squeaked through in the morning, needing 21 holes to eliminate Katie Miller, 31, of Jeannette, Pa., in the quarterfinals. Potter never trailed against No. 10 seed Miller, but also could not pull away from her tenacious opponent.

“I wanted to take care of the shots and make sure that she had to beat me with pars and birdies,” said Potter, who won the match with a par 5 on the 21st hole after Miller found the trees to the left side of the 12th fairway. “You don’t want someone winning with a bogey. It happens, but I’m just trying to play consistent enough that pars and birdies are what it’s going to take to win a hole against me.”

Potter then cruised in the semifinals, winning five of the final seven holes to notch a 4-and-3 win over Patricia Schremmer, 51, of Honolulu, Hawaii.

Should Potter win on Thursday, she would become just the fifth player to win multiple U.S. Women’s Mid-Amateur titles, joining Sarah LeBrun Ingram (1991, 1993, 1994), Port (1995, 1996, 2000, 2011), Meghan Stasi (2006, 2007, 2010, 2012) and Thompson (1990, 1997). She is already the only female left-handed champion in USGA history.

“All I'm trying to do is enjoy the moment,” said Potter, the director of marketing for the Indiana Golf Office. “I know how hard it is to get back here, and take that in and hopefully take that momentum into tomorrow, as well.”

Schremmer, a first-time Women’s Mid-Amateur competitor, earned one of the biggest comeback victories of the championship in the quarterfinals. After being 3 down through four holes to four-time champion Meghan Stasi, Schremmer converted an improbable 18-foot birdie putt from just off the green at No. 18 to clinch her berth in the semifinals.

“I hit the ball really well the last 14 holes in the morning round, and putting, I kind of was getting the hang of the greens,” said Schremmer, who is in the field of the 2016 U.S. Senior Women’s Amateur Championship, which begins Saturday at Wellesley (Mass.) Country Club. “I had a really nice match this afternoon with Julia. I just got behind and I didn't recover.”

Johnson and Potter are now fully exempt into the 2017 U.S. Women’s Amateur Championship, which will be conducted Aug. 7-13 at San Diego Country Club in Chula Vista, Calif. Additionally, the winner receives a 10-year U.S. Women’s Mid-Amateur exemption, while the runner-up receives a three-year exemption. All four semifinalists receive a two-year exemption.