LAKE FOREST, Ill. (AP) — Jason Day’s easy win Sunday at the BMW Championship confirmed what his rivals have known for several weeks now: The Aussie is the best golfer on the planet.

Day’s mostly stress-free final round of 2-under 69 at Conway Farms gave him his fifth win on tour this season, his second in the FedEx Cup playoffs and vaulted him past Jordan Spieth and Rory McIlroy into the No. 1 spot in the world ranking.

The Australian zoomed out to a big lead by shooting 61 and 63 in the first two rounds and was never seriously challenged after that. His 22-under total tied for the second-lowest on tour this year and was good for a six-shot victory over rookie Daniel Berger. Scott Piercy finished third, seven strokes back.

“To be honest, I’ve had terrible sleep over the last few nights thinking about getting to No. 1, thinking about winning this tournament ... because I had such a big lead and I didn’t want to give it back,” Day said.

The win also made Day the front-runner in the 30-man field heading into the series finale at East Lake in Atlanta. But it won’t help his rivals rest any easier.

“Whatever Jason Day is doing, or which course he’s playing, it’s ridiculous,” said Danny Lee, who’s at No. 19.

If Day manages a win in Atlanta, it could make the race for Player of the Year considerably closer than anyone expected after Spieth won the Masters and U.S. Open and appeared to lock up the award.

But Day’s play since the British Open — he won the PGA Championship for his first major and his 101-under par in seven starts since — has narrowed the gap. And when Rickie Fowler was asked to pick between the two, he replied “I’m glad it’s not my decision” — forgetting that he’ll have to cast a ballot at season’s end.

After missing the finale at East Lake by a shot each of the last two seasons, Harris English shoe-horned himself into the 30th spot with a birdie at the 18th.

“Awesome,” he said.