In a harsh critique of his own performance, the former World No.1 says he expected more from the 2018 season despite two US Tour victories and a runner-up among five top-10 results and 14 top-25s.

Despite earning almost $5million from 19 starts, Day feels his poor results at the majors – failing to finish inside the top-15 at all four of golf's biggest events – influenced his negative assessment.

The 30-year-old also fizzled in the first three legs of the $US67million FedExCup playoffs, with his best result a tie for 20th.

“This year, even though I've had two wins, has been disappointing,” an honest Day told AAP.

“I didn't play good in the majors and I could have played a lot better in the first three playoffs.

“I need to sit down with the team and go over certain things so I can work out how to change that (for next year).”

Day admits that a strong finish at this week's Tour Championship and Australia's first FedExCup would give him a different outlook on the season. PHOTO: Hunter Martin/Getty Images

Day concedes he continually measures himself against his breakout 2015 campaign, when he captured the US PGA Championship among five US Tour wins that catapulted him to a debut World No.1 stint.

“I've got high expectations if myself,” Day said.

“Even a five win year, I still looked for ways to improve because there is always something to improve and I feel I can win even more than (five).

“It's a good thing I look at it that way because if you don't, you're not pushing yourself to your absolute best.”

However, the 12-time PGA Tour winner says capturing this week's Tour Championship in Atlanta and having a series of results fall in his favour to claim the FedExCup would allow his season to end on a high.

Victory at the 30-man finale would net the Queenslander almost $US1.6million, while he would also pocket a $US10million bonus should he pull off the inconceivable and become the first Australian to win the FedEx title.

“Winning the FedExCup and the Tour Championship would definitely sway that feeling (of disappointment),” Day said.

Day's mixed results have left him 12th on the FedEx standings at the Tour Championship, while fellow Queenslander Cameron Smith is the leading Australian in 10th.

Smith will make his Tour Championship debut, while Marc Leishman rounds out the Australian tilt at East Lake Golf Club and he sits 29th on the standings.

- Evin Priest, Australian Associated Press