LAKE FOREST, Ill. — Jason Day has plenty of rivals at the moment, but very few peers.

Day’s runaway victory Sunday in the BMW Championship vaulted him to No. 1 in the world ranking, backing up a boast the then little-known Australian made during a conference call with reporters in 2007 — and for which he was roasted on more than one occasion since.

“I remember sitting on my mom’s bed and thinking that (predicting he’d be No. 1 someday) might not go over too well,” laughed Day, who turns 28 next month.

It didn’t.

“I expected to get a little bit (of criticism), but not the response that I got from practically everyone,” Day recalled, another championship trophy poised within arm’s reach.

His 2-under, final-round 69 and 22-under total at Conway Farms was good for a six-shot victory over rookie Daniel Berger. Scott Piercy finished third, seven strokes back.

The win was Day’s fifth on tour this season and his second in the FedEx Cup playoffs. In addition to leap-frogging Jordan Spieth and Rory McIlroy to claim the top spot in the world ranking, it made him the front-runner in the 30-man field heading to East Lake in Atlanta next weekend for the series finale.

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