Great Scott, Aussie's still going strong as Clark wins

Adam Scott has displayed his enduring class once more to qualify for golf's lucrative Tour Championship at age 46.

As American Wyndham Clark held off superstar Rory McIlroy to claim the PGA Tour's second and penultimate play-off event in Missouri, Scott sealed his place at the season-ending showpiece with his own brilliant final round.

On a day of tough scoring at the Bellerive Country Club, Scott closed with a three-under-par 67 to finish in a tie for 16th at six under.

Scott, who is 28th in the FedEx standings, will join fellow Australian Min Woo Lee in the hunt for the $US10 million winner's cheque at next week's season-ending championship in Atlanta.

The former world No.1 will be contesting his 14th Tour Championship, 20 years after winning one of golf's most prestigious trophies.

Lee will be making his Tour Championship debut after qualifying for the elite 30-man field in 20th position in the season-long points race.

The 28-year-old tied for 47th in St Louis at two over after posting a final-round 71 as Clark held his nerve down the stretch to claim the spoils.

After starting the day with a five-stroke buffer, the two-time US Open champion relinquished his huge lead with three bogeys in his first 10 holes.

But he steadied with birdies on 16 and 17 as McIlroy's challenge ended with a gut-wrenching bogey six on the second-last hole.

With a final-round 70, Clark won by three shots at 17 under, with fellow American Patrick Cantlay (68) snatching second.