Jason Day has likened his emergence as golf's world number one to if Rory Mcllroy and Jordan Speith had a baby.

But day insists his new status as world number one 'doesn't feel like much' as he targets a fifth win in his last seven events to ensure it is not a brief stay at the top of the rankings.

Day overtook Rory McIlroy after winning the BMW Championship on Sunday, his second win in three FedEx Cup play-off tournaments and fifth of the year.

Jason Day is top of golf's world rankings, replacing Rory Mcllroy after winning the BMW Championship

Australian Day played down the significance of being world no 1, saying: 'To be honest it doesn't feel like much'

The 27-year-old is 101 under par for his last seven events, including a major championship record of 20 under in winning the US PGA Championship at Whistling Straits.

However, with the top three of Day, McIlroy and Jordan Spieth separated by less than one ranking point, the Australian knows he will need to keep winning to stay ahead of the chasing pack.

'I know I have put the work in and have done so much to get to where I am, but to be honest it doesn't feel like much,' Day said of his ranking ahead of the Tour Championship.

'It's not like that one big shining moment or one big sense of relief that I've done it now.

Day pictured in his practice round ahead of the TOUR Championship By Coca-Cola in Atlanta, Georgia

'It makes me a lot more hungrier to try and keep my position at number one because I want to try and extend it, but I am still the same guy as I was the week before I won and got to number one. I still feel the same.

'It's like Jordan Spieth and Rory McIlory had a baby, and I was it.

'It's great to see my name up there, it's pretty cool to be the best player on the planet, but I understand that to be the best you have to win consistently so whatever I am doing right now, I need to keep doing that because that's my blueprint that has been working.'

The new world number one has said that he can't stop chasing wins and wants the $10million Fedex Cup prize

Any of the 29 players in the field in Atlanta - Jim Furyk has withdrawn with a wrist injury - can win the USD10million bonus for lifting the overall FedEx Cup title, but only the top five are assured of doing so by winning at East Lake.

Day, who could theoretically finish 28th and still claim the bonus, said: 'I wish it was the old format where I could cruise to a FedEx Cup win, that would have been nice. But now obviously the top five do control their destiny.

'Being number one does give me a better chance if I don't win the tournament but I am just trying to get to my eighth (career) win now. When I look at wins I've had, to me personally it feels low.

Day jokingly said it was like Rory Mcllroy (left) and Jordan Spieth (right) had a child and it was him

'That's what my mentality is with wins, I can't stop chasing them. I have to try and get as many as I can before my career is done and this week is a perfect opportunity to add to it because it is a smaller field.'

Day struggled to come up with ideas for what he would do with the $10million, but admitted it would be on his mind if he was in contention on the back nine on Sunday.

'It did in 2011 and I choked,' joked Day, who began the final round two off the lead but shot 71 to finish sixth.

Day, Spieth, Rickie Fowler, Henrik Stenson and Bubba Watson are the players with their destiny in their own hands, Stenson seeking to win the FedEx Cup title for the second time in three years.

But this time the Ryder Cup star could do so without winning a single tournament all season, with joint third possibly good enough thanks to the way the points accumulated through the year are reset before the Tour Championship.

'You can be world number one without winning a tournament in a year and you can win the FedEx Cup or Race to Dubai or anything else without winning a tournament,' said Stenson, who has finished second, second and 10th in the play-off events.