Casey brilliantly grabbed a sixth hole eagle and five birdies in a third round 65 and take a two-shot lead at 12-under in the final round on the East Lake course in Atlanta.
The Americans Kevin Kisner (64) and Xander Schauffele (65) share second place on 10-under par while Justin Rose struggled with a 71 to be sharing ninth place on five-under.
If Casey is successful he would pocket the $US 1.5m first prize and the FedEx Cup trophy bonus of $US 10m.
However, a number of scenarios need now to unfold and all hinging on Casey winning the 2016/17 season-ending event.
To win the FedEx Cup Casey needs the following:-
· Must win the Tour Championship
· Jordan Spieth must finish in a three-way tie for 4th or worse (Currently T13th)
· Justin Thomas must finish in a three-way tie for 3rd or worse (T6th)
· Dustin Johnson must finish in a three-way tie for 2nd or worse (T13th)
· Marc Leishman must finish in a two-way tie for 2nd or worse (T22nd)
· John Rahm must finish 2nd or worse (T6th)
The big plus for the hugely affable 40-year old Cheltenham-born Brit is that his nearest rival for the FedEx crown and Open Champion, Jordan Spieth trails eight shots behind sharing 13th place and with a lowest score in three days of an opening 67.
“Unfortunately, I’m not really in control of my own destiny at this point, but I’ll go out tomorrow, try and shoot a really solid round of golf and then do some cheerleading, so that’s kind of the plan tomorrow,” said Spieth.
In contrast, Casey will head to the final day of the most important 18 holes in his 18-year pro career with destiny very much in his hands as he also looks to draw upon his last day showing a year ago when he produced a closing 64 to share fourth.
“My last round here last year was a 64 and I will take a 64 tomorrow,” said Casey.
Casey kick-started his round in stunning manner with birdies at three and five and then sandwiching a 10-foot eagle putt on the par five, sixth hole in between adding a birdie at seven.
He dropped shots at eight and nine before birdies at 11 and then draining a 40-footer for birdie on 17.
“It was a great stuff and then to eagle five after a great 239-yard 4-iron shot was a huge bonus,” he said.
“It was a little disappointing to drop those shots on eight and nine but to play the inward nine in two-under, and also nearly birdie, 18 was very pleasing.”
It’s been eight long years since Casey captured his first and still only PGA Tour triumph in winning the 2009 Shell Houston Open.
However, in the intervening eight years he has been the ‘Mr. Consistency’ has enjoyed 47 top-10s, including eight in 2017, and is also tied for the most in any one PGA Tour season in his career.
And Casey’s consistency in the 2016/17 season is unmatched in any other season of his career while he’s missed just one cut and has recorded 16 top-25s in his 22 starts.
Casey has been absent from Phoenix home for two weeks during which time partner and former Gadget Show host, Pollyanna Woodward gave birth on September 11 to daughter, Astasia.
Now Casey, who has also 16 other wins around the globe including 13 on the European Tour, is set to celebrate victory and revealing that soon after his son, Lex won born he captured the 2014 KLM Open and his last win anywhere.
“Really, the last chance I had of winning was at the Deutsche Bank in Boston last year and that is a win I did let slip,” he said.
“But the thing is now I want to be able to win and I want my name on a trophy here at East Lake.
“I will tell what is really cool tomorrow is that I am playing with Kevin Kisner and we both are celebrating having children with my little girl born on September 11th and Kisner’s son born a couple of days prior to that.
“The thing also I won a week after Lex was born back in September 2014 at the KLM Open, so there must be something about guys having a second child as Kisner’s boy was his second.
“Of course, there is more important things and I am not trying to belittle the importance of tomorrow but I am sure I will have a relaxed nature because of what Kevin and I have gone through recently.”