Being his sport’s top player is an experience that Day could come to be comfortable with, but hitting the summit for the first time had him struggling to explain his emotions.

“I’m not really thinking about it right now. It doesn’t feel real,” he told Sky Sports 4.

“Knowing the Shark (Norman) spent 331 weeks up the top of the world ranking list – a very long time – and next week’s going to be my first week.”

Day, having recorded scores of 61, 63 and 69 in his first three rounds, finished on 22 under par after carding three birdies and a bogey on Sunday with nearest challenger, American Daniel Berger, only managing to equal his two-under-par final-round effort.

The 27-year-old Australian added: “I feel good. Just all the work ever since I was a little kid trying to get to number one in the world and today I did it, which was great.

“To have an opportunity, knowing I had to win this week to gain that spot, and stepping up and doing it was fantastic.”

Day begins his reign at the summit by playing at The Tour Championship, starting on Thursday, and the Queenslander is in the driving seat to scoop the FedEx Cup.

“I’m going to take Monday and Tuesday off,” he said.

“I’m going to go home (to Westerville, Ohio) and then I’ll fly down to Atlanta on Tuesday night. Try to get as much rest as possible. The last two days have been very stressful for me.

“Emotionally it’s been very up and down inside. I may not show it but inside I’m going up and down.

“I’ve got to try to reset everything. After this week, after my celebration tonight, it’s done. I’ve got to get into next week and try to win the FedEx Cup.”

Berger could have been closer to Day having registered five birdies on Sunday but, unfortunately for the 22-year-old, they were accompanied by three bogeys in a topsy-turvy round.

Scott Piercy made birdie at the final hole to clinch third at 15 under and JB Holmes, Rickie Fowler and McIlroy were tied for fourth one further shot adrift.