Allen closed with 5-under 65, also birdieing the par-5 18th in regulation to match Browne at 13-under 197 at Rock Barn. Browne shot 64, charging to the lead with seven birdies over a nine-hole stretch.
In the playoff, Allen put his second shot within 10 feet, and Browne hooked his second shot badly into the rough off the green. Allen’s eagle putt just lipped out, and he tapped in for birdie. Browne missed a 40-foot putt for birdie and settled for par.
Second-round leader Bernhard Langer had 69 to finish third at 11 under.
EUROPEAN TOUR: In Perth, Australia, former top-ranked amateur Jin Jeong won the Perth International on Sunday for his first professional victory, beating Ross Fisher with a par on the first hole of a playoff.
Jeong, the South Korean player based in Melbourne, closed with 3-under 69 to match Fisher at 10-under 278 at Lake Karrinyup. Fisher finished with 68.
LPGA TOUR: In Incheon, South Korea, Amy Yang beat South Korean compatriot Hee Kyung Seo in a playoff on Sunday to win the KEB HanaBank Championship.
Yang shot 69 in the final round while Seo had 68 as both players ended regulation at 9-under 207 before Yang won the playoff.
ONEASIA TOUR: In Cheonan, South Korea, Kang Sung-hoon won the Korea Open on Sunday, which ended in a dispute after Kim Hyung-tae was informed of a two-shot penalty when he lead by one shot with two holes to play.
Kim, who started the final round with a four-shot lead, argued that he never grounded his club on the 13th hole. The OneAsia Tour said he discussed the violation with tournament officials for two hours. The Korean Golf Association voted 5-3 against him.
It was an awkward ending for Kang, who closed with 2-under 69 for a one-shot victory over Kim, Rory McIlroy (67) and two others.
The four-way tie for second was the best for McIlroy since he was runner-up at the Texas Open in April.
Kim had a one-shot lead when he was notified on the 17th tee that he and playing partner Hong Soon-sang grounded their clubs in an area on the 13th deemed to be a hazard. They finished their rounds before reviewing the violation (Rule 13-4) with officials.
The two-shot penalty gave Kim a closing 77.
The OneAsia Tour said Kim left the course after the trophy presentation.