Hannah O’Sullivan, 17, of Chandler, AZ., won the 2015 U.S. Women’s Amateur Championship at Portland Golf Club, earning a 3-and-2 victory over Sierra Brooks, 17, of Sorrento, FL.

After trailing by three holes through 15, O’Sullivan steadily inched closer, cutting the deficit to 1 down at the 18-hole break, squaring the match through 23 holes, taking the lead on the 24th hole and making a 4-foot par putt on the 34th green to seal the victory.

O’Sullivan and Brooks both receive exemptions into the 2016 U.S. Women’s Open Championship, which will be contested July 7-10 at CordeValle, near San Jose, CA., just 30 minutes from where O’Sullivan grew up in suburban San Francisco. O’Sullivan also receives a 10-year exemption into the U.S. Women’s Amateur and one-year exemptions into the Ricoh Women’s British Open Championship, ANA Inspiration and Evian Championship. Brooks receives a three-year Women’s Amateur exemption.

Both competitors played exceptional golf during Sunday’s 36-hole final match, with O’Sullivan playing to 7 under par and Brooks to 3 under, with the usual match-play concessions. O’Sullivan struck first, winning the par-4 third, but Brooks took holes 5-6 for a 1-up lead. O’Sullivan squared the match through seven holes, and Brooks regained the 1-up advantage with a 10-foot birdie on No. 9.

For the next several holes, the momentum swung notably in Brooks’ favor. O’Sullivan flew the green on No. 10 and stubbed her chip, with the resulting bogey giving Brooks a 2-up lead. She extended the advantage to 3 up with another birdie on the par-4 14th.

“This morning, I was striping it, and everything was really clicking,” said Brooks, who has verbally committed to attend and play for Wake Forest University for 2016. “I didn’t miss a lot of shots.”

O’Sullivan returned to her early form on the par-4 16th, where she drained a 30-footer for birdie and cut Brooks’ lead to 2 up. Brooks then stumbled on the par-5 18th, finding a left fairway bunker off the tee. Her escape shot clipped some low-hanging trees and failed to advance more than 20 yards, ultimately resulting in a bogey that dropped her advantage to 1 up going into the lunch break.

“I felt like I wasn’t playing very well at all the first 18, but I fought back and I still shot 1 under,” said O’Sullivan, who plans to join the University of Southern California golf team in the fall of 2016. “I knew the game was definitely there, and I had the opportunities.”

O’Sullivan took her first lead since the fourth hole with a 5-foot birdie on No. 24. A second consecutive birdie on the 25th hole, this one from 6 feet, extended O’Sullivan’s advantage to 2 up.

Brooks fought back with a birdie on No. 27 to pull within one, and the match again went to all square when O’Sullivan missed a 6-foot par putt on the 29th hole.

The match turned squarely in O’Sullivan’s favor on No. 30. Brooks’ 40-footer for birdie just missed to the left, and O’Sullivan dropped a 30-footer of her own for a 1-up lead. She went 2 up after Brooks failed to get up and down from a greenside bunker on No. 32, and gained the 3-up advantage by nailing a 7-foot birdie on the 33rd hole.

Brooks had an opportunity to extend the match on No. 34. Her long birdie putt was on line, but heartbreakingly squeaked just past the hole to the left.

The 2015 U.S. Women’s Amateur Championship is open to female amateur golfers with a Handicap Index® not exceeding 5.4. It is one of 13 national championships conducted annually by the United States Golf Association, 10 of which are strictly for amateurs.