JASON Day claimed his seventh US PGA Tour victory on Sunday to take over the world No. 1 ranking, becoming the third player in as many weeks to capture golf's coveted top spot.
The 27-year-old Australian went wire to wire, closing with his second straight two-under 69 to win by six strokes at the BMW Championship, the third of four tournaments in the FedEx Cup play-offs.
"All I want to do is win," said Day, who has won four of his last six tournaments, including his first Major at last month's PGA Championship. "Yesterday and today were the toughest rounds I have ever had to play in my life."
The Australian began his final round with a six-shot lead over a star-studded pack that included Rory McIlroy, whom Day toppled from the No. 1 spot, and US Open and Masters winner Jordan Spieth - who was ranked second going into the event after trading the top spot with McIlroy.
Several players tried to make a charge at Day on Sunday but the Queensland native was not going to wilt. He held them off by staying out of trouble and making sure he maintained his aggressive approach around the greens.
He added a few birdies for good measure, like the one on the par-four 16th when he drained a 15-foot putt, and then on his closing hole to reach 22-under 262.
Day said the 2015 Open Championship at St Andrews in July was the spark he needed to get his mind focused on winning consistently.
"Ever since the Open Championship, something changed in my head and I felt like it was my time to start winning tournaments. Ever since then, it has been a phenomenal run," said Day, who was struck down at the US Open in June by vertigo issues.
American Daniel Berger shot a 69 to finish second on 268 while Scott Piercy (70) finished third, seven strokes adrift of Day.
McIlroy (70), J. B. Holmes (68) and Rickie Fowler (69) tied for third at 270.
Spieth shot a 70 to finish tied for 13th.
Day becomes the youngest Australian to reach No. 1 and the third in history behind Greg Norman and Adam Scott.
It was also Day's fifth win of this year as he joins Tiger Woods and Vijay Singh as the only players in the last 20 years to win at least that many in a season.