Staked to a five-shot lead, Leishman made back-to-back birdies late in the final round Sunday to put away the final challenge, then closed with a birdie for a four-under-par 67 to set the tournament record and win by five over Justin Rose and Rickie Fowler.
It was Leishman's second victory this year, and it sends him to East Lake as the No. 4 seed in the FedEx Cup, giving him a clear shot at the $10-million prize.
The timing could not have been better for the 33-year-old Australian. In his last event two weeks ago, he lost a two-shot lead on the back nine at the TPC Boston and said that loss stung more than most.
“I had a few scars from a few weeks ago,” Leishman said. “I was just really, really determined to not let that happen again. Got it done.”
Rose is the only player who got within two shots of the lead, only for Leishman to answer with a 30-foot birdie putt on the 15th hole and a 10-footer for birdie on the 16th. Rose closed with a 65.
Fowler made a late run when he was too far back, and he needed one more birdie on the 18th to grab the No. 5 seed for the FedEx Cup finale next week at the Tour Championship. He ripped driver off the fairway and over the stream to the back rough. It was a bold play that preceded a pair of meager efforts — a chip that came up 25 feet short, and a birdie putt that didn't to the hole. He closed with a 67.
Jon Rahm birdied four of his last five holes for a 67 and will be the No. 5 seed.
Jordan Spieth shot 65 to tie for seventh and kept the No. 1 seed, followed by Justin Thomas, Dustin Johnson, Leishman and Rahm. The points are reset to give all 30 players at East Lake a mathematical chance, but the top five seeds only have to win the Tour Championship to capture the FedEx Cup.
As usual, the only drama at Conway Farms was who made it to East Lake, and a pair of PGA Tour rookies delivered.
Xander Schauffele, who won The Greenbrier Classic in July, opened with 10 pars and two bogeys and was not even in the picture until the San Diego native played his final six holes in 6-under par, including a 30-foot eagle when he drove the green on the par-four 15th.
Patrick Cantlay fell out of the top 30 when he took bogey on the 16th hole. Needing a birdie to get into the Tour Championship, he hit a hybrid onto the green to 50 feet, left his eagle attempt some 10 feet short and calmly holed the putt to get in.
Cantlay returned to golf after a three-year break from a back injury that nearly ended his career, and the death of his close friend and caddie, Chris Roth, who was hit by car as they walked to dinner. The former UCLA star made it to the Tour Championship despite playing only 11 events this year. Being in the top 30 gets him into the Masters, U.S. Open and British Open next year.
Masters champion Sergio Garcia injected more drama than necessary. He figured he needed a par on the final hole to get into the top 30 when a bogey would have worked. His second shot was on the rocks in the stream, and after taking close to 30 minutes on a drop, he smacked it over the green into the grandstand, got more relief, and then got up-and-down for his par.
Phil Mickelson wasn't so fortunate. He made three bogeys on the front nine and tried to get back in the game with an eagle on the reachable par-four 15th. Needing an eagle on the 18th hole to make it to East Lake, Mickelson's 140-foot pitch-and-run hit the hole and popped out.
Nordqvist captures Evian Championship
Anna Nordqvist beat unheralded American Brittany Altomare in a playoff under driving rain and hail at the first extra hole to win the Evian Championship in Francey. Nordqvist sank a four-foot putt for bogey five on the soaked 18th hole while 102nd-ranked Altomare had a six.
The 30-year-old Swede earned $547,500 for winning her first major since the 2009 LPGA Championship. Altomare got $340,000 for only her second career top-10 finish.
Nordqvist and Altomare both shot 66 for nine-under totals of 204. It was a 54-hole event after weather-affected play Thursday was scrapped.
Second-round leader Moriya Jutanugarn of Thailand and two-time major winner Lydia Ko of New Zealand fell out of the playoff by dropping shots on the 18th.
Nordqvist's victory ensured 10 different major winners in the last two seasons.
Wattel takes KLM Open title
Romain Wattel shot a steady two-under 69 Sunday to finish 15 under and win the KLM Open in Spijk, Netherlands, the Frenchman's first victory in 187 tournaments on the European Tour.
Wattel, who posted a seven-under 64 to move into contention on Saturday, had four birdies and two bogeys in the final round and parred his final seven holes to close out his maiden win.
Overnight leader Kiradech Aphibarnrat of Thailand blew his chance of victory by finding the water and shooting double bogeys on the 15th and 18th holes. He finished on 12 under in a five-way tie for ninth.
Aphibarnrat's implosion on the 18th left Austin Connelly of Canada alone in second place after he shot his second consecutive round of 66 to finish one shot behind Wattel. Six players, including Lee Westwood and fellow Briton Eddie Pepperell, tied for third at 13 under.