You will not earn this achievement by winning the WGC-FedEx St. Jude Invitational.
This is in fact for the final tournament, le TOUR Championship.
To qualify for this tournament, you'll need to be top 30 in the Fedex Ranking.
Being first at the FedEx ranking will help you a lot by letting you start this tournament with -3.
During my first season, the 2nd player had 7.500 FedEx points.
If you're short on point, remember that the 2 last tournaments can help you a lot.
Giving you 2.000 points for the win during "The Northern Trust" but you need to be top 125 to qualify
Then giving you 2.000 points for the win during the "Trios Championship" but you need to be top 70 to qualify.
There is no difficulty requirement so if you're not feeling at ease with the AI, remember you can set everything up to easy !