LAKE FOREST, Ill. – Jason Day was sitting on his mother’s bed in Australia when he first publicly expressed his desire to be No. 1 in the world. Day, who’d just turned 20, was on a conference call with Australian media as he prepared for his first PGA Tour season.

He talked about his desire to overtake Tiger Woods as the world’s best player. Day was worried about the potential backlash almost as soon as the words left his lips, though.

This was November 2007, when Woods was still up to his dominant ways. Critics said Day was both brash and delusional. The thought of anyone but Woods possessing the top spot in the Official World Golf Ranking seemed unfathomable at the time. Day was surprised by the severity of the backlash, though.

“He was really upset,” Day’s longtime coach and caddie Colin Swatton recalled. “He said, ‘What did I say wrong? Everyone wants to be the best golfer in the world. They don’t want to be second or third, do they?’”

That was nearly eight years ago, though, and so much has changed. Woods is sidelined by another surgery and Day has become a dominant force. He reached No. 1 with a six-shot win at the BMW Championship, where he shot 22-under 262 (61-63-69-69). He tied the PGA TOUR’s 36-hole scoring record en route to a victory waltz.

It was the latest impressive victory in Day’s torrid late-season stretch. He’s won four of his past six starts, including the PGA Championship and two of the first three FedExCup Playoffs events. His average margin of victory in his past three wins is five shots. He’ll arrive at the Tour Championship as the No. 1 player in both the world ranking and the FedExCup. His five wins this season are the most on Tour.

“I’d love to say, ‘I told you so’, but that wouldn’t be very nice,” Day said. “It’s OK to dream big. It’s OK to say what you want to do.”

He’s dreamt of being No. 1 since he was a kid, envisioning himself standing atop the globe above the millions of people who play this game. His imagination was stoked as he watched Tiger Woods win the 1997 Masters and read Woods’ instructional book.

Swatton recalls when Day, 14 or 15 years old at the time, first asked if becoming No. 1 was a feasible goal. Swatton was sitting in his office at The Kooralbyn International School when Day walked in the door.

“He came in and just said, ‘Do you really think I can be the best player in the world?’ Swatton recalled as he stood near the 18th green at Conway Farms Golf Club. “I said, ‘Absolutely. You just have to listen, be patient, work hard and eventually you’re going to get there.’

“I had every reason to believe he could get there one day.”

They devised a plan to reach No. 1. It was divided into four “buckets”: technical, tactical, physical and mental. The plan called for him to reach No. 1 at age 22. He’s five years late, but as Day joked, “it’s better late than never, right?”

The mental aspect was the last bucket that was filled, Day said. He’s recently started to feel the way he did as an amateur golfer, when he’d stride to the putting green knowing that he was the best player there.

He knew a win at this week’s BMW Championship would guarantee him the No. 1 spot, regardless of how Jordan Spieth and Rory McIlroy fared. Day was dominant from the start. He led by at least four shots after each round, and was six shots in front entering the final round. His large leads made it difficult for him to sleep, knowing that he was on the verge of accomplishing this lifelong goal.

“It’s been very difficult for me to downplay getting to No. 1 because I really wanted to reach this goal for a very long time now,” he said.

The BMW victory didn’t elicit the same emotions as his PGA Championship win, though. It’s been difficult to wrap his mind around all that he has accomplished since leaving The Open Championship just two months ago. At St. Andrews, he experienced another close call in a major. Everything has gone right for him since then.

“It just feels normal,” Day said about reaching No. 1. “I feel like I did yesterday, the same. Once again, I’m just a regular guy like everyone else.

“Everyone has dreams. As long as you stick to them and work hard, you can accomplish anything.”