Berger, 24, is the fourth repeat victor at St. Jude and the first since David Toms did it in 2003 and '04.
In a keenly-fought contest, which at one point included nine players tied for the lead, Berger picked up a birdie on 15 to move clear.
"I'm playing good. I'm confident on the greens".
"I feel great, I feel like I broke through", she said.
The 44-year-old Cink said he was "a little tired" after coming through a sectional qualifier for the second major of the year.
European - Felipe Aguilar of Chile shot a 7-under 65 to build a two-stroke lead over a group of three in the opening round of the Lyoness Open in Atzenbrugg, Austria.More news: Supergirl Has New Showrunners For Season 3
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Schwartzel should open Round 3 as the favorite given the lack of in-form players around him near the top of the leaderboard.
LPGA - Suzann Pettersen and Mi Hyang Lee each shot an 8-under 64 to share the first-round lead at the Manulife Classic in Cambridge, Ontario.
Jutanugarn's drive found the long grass on the side of the par-four No. 18, but she recovered with an approach shot that left her pin-high.
Jutanugarn finished with a three-under 69 in the final round and was tied with Thompson (72) and Chun (70) at 17-under 271.
He will tee it up in his third US Open on the back of a strong season, with four top-10 finishes and five top-25 finishes.
Phil Mickelson made a dramatic charge and grabbed a share of the lead following his fifth birdie of the day at No. 10, but he doused his momentum and his chances with a triple bogey at the par-4 12th. Perrine Delacour (62) of France and American Lindy Duncan (65) were one shot back.
CHAMPIONS: Brandt Jobe won the Principal Charity Classic by one shot in Des Moines, Iowa, shooting 69 to finish at 14-under 202 for his first victory since taking a tournament in Japan in 1998.