Sierra Brooks (left) of Florida and Hannah O'Sullivan of Arizona (USGA photo)

Brooks, 17, of Sorrento, Fla., took a 4-and-2 win over Bethany Wu, 18, of Diamond Bar, Calif., while O’Sullivan, 17, of Chandler, Ariz., came back from 3 down to earn a 1-up win over Mathilda Cappeliez, 17, of France.

By reaching the final match, Brooks and O’Sullivan earned exemptions into the 2016 U.S. Women’s Open Championship, which will be contested July 7-10 at CordeValle, near San Jose, Calif. The winner will receive a 10-year exemption into the U.S. Women’s Amateur, while the runner-up will receive a three-year exemption.

In a match between great friends, Brooks jumped out to a 2-up lead after three holes and never looked back in her triumph over Wu.

“It's so tough playing my best friend, because I'm rooting for her when I'm out there, too,” said Brooks, the No. 5 player in the Women’s World Amateur Golf Ranking™ (WAGR) and the top-ranked American. “I really don't want to see her struggle at all, and I know she had a bit of a tough day, so that was hard to watch. But I definitely played really solid. It’s bittersweet.”

Brooks extended her lead to 3 up with a par on the sixth hole, but Wu made birdie on No. 8 to cut the margin to 2 up. Brooks responded by winning the ninth hole with a solid two-putt from 12 feet for par, while Wu put too much speed on her par approach and it lipped out of the hole.

On the second nine, Brooks and Wu halved the first six holes with pars until Brooks birdied the par-4 16th to close out the victory.

Brooks, who was named 2015 American Family Insurance All-USA Girls Golf Player of the Year by USA Today, said one of the keys to her success was her creativity.

“If I hit it in the trees, I like to try to, if I can, bend a shot around to try to get to the green,” said Brooks, who also defeated Wu in the semifinals of the 2014 Polo Junior Classic. “I'd say that's definitely one of my strengths.”

For the second consecutive match, O’Sullivan rallied from a multi-hole deficit to earn a comeback victory. Cappeliez won Nos. 2, 3 and 8 to build a 3-up advantage before O’Sullivan, who was 2 down through 10 holes in her quarterfinal match, began her rally with a par on No. 9 to win the hole.

Bethany Wu (left) congratulates her close friend Sierra Brooks on her 4-and-2 semifinal victory on Saturday. (USGA/Steven Gibbons)O’Sullivan, the No. 10 player in the WAGR, birdied the par-4 11th hole and made par on No. 12 to square the match. After halving No. 13, O’Sullivan made par on the 14th to take her first lead of the match. Cappeliez won No. 16 with a par after O’Sullivan hit her approach shot into the water, but O’Sullivan responded by making a 20-footer from the fringe for birdie on the 17th hole.

“I guess I didn't really think that much while I was over the putt,” said O’Sullivan, who was co-runner-up in the 2015 U.S. Women’s Amateur Four-Ball Championship at Bandon Dunes. “I just picked my target and stroked it, and to see it go in was incredible.”

O’Sullivan and Cappeliez halved the 18th hole with pars, which gave O’Sullivan a 1-up victory.

Brooks and O’Sullivan will meet for the fourth time in 2015, with the three previous matches taking place at the Wyndham Cup. The pair halved their singles match on Day 3 of the competition after team matches on each of the first two days.

Brooks and O’Sullivan were teammates on the 2014 USA Junior Ryder Cup Team in Scotland, but were not paired together. They will be teammates on the 2015 USA Junior Solheim Cup Team in September in Germany.

“[O’Sullivan is] a very solid player,” said Brooks. “Ball-striking-wise, she hits it dead straight almost every time, and anywhere inside 10 to 5 feet, it's going in. It’ll definitely be a tough match tomorrow.”

“We’ve both grown up together and we're both really good at golf, so it's going to be a lot of fun tomorrow,” said O’Sullivan. “It's really an incredible experience.”

The 2015 U.S. Women’s Amateur Championship is open to female amateur golfers with a Handicap Index® not exceeding 5.4. It consists of 36 holes of stroke play followed by six rounds of match play, with the championship scheduled to conclude with a 36-hole final on Sunday, Aug. 16.

Sunday’s 36-hole final will be broadcast on Fox Sports 1 from 4 p.m. to 7 p.m. EDT. Bonus coverage will be streamed live on usga.org from Noon to 2 p.m. EDT.

The U.S. Women’s Amateur Championship is one of 13 national championship conducted annually by the United States Golf Association, 10 of which are strictly for amateurs.