- Billy Horschel wins Tour Championship at East Lake
- Horschel claims $10m bonus for clinching FedEx Cup crown
- Rory McIlroy and Jim Furyk tied for second three shots back
- McIlroy's chances ended by mid-round collapse
Billy Horschel is $11.4m richer after getting the better of world number one Rory McIlroy and fellow American Jim Furyk to win the Tour Championship Sunday and clinch the FedEx Cup.
His three-shot victory at East Lake has capped a remarkable three weeks for the 27-year-old, who won the preceding BMW Championship after finishing second in the Deutsche Bank Championship.
He benefited from a mid-round collapse by McIlroy, who had started the day with Horschel in the joint lead.
A double bogey on the short sixth and three further dropped shots around the turn saw the Northern Irishman fall out of contention before three birdies in the final four holes restored a measure of respectability to his round.
Furyk emerged as the main challenger to Horschel, drawing level with him before a 31-foot birdie putt put the eventual champion in a lead he never relinquished.
Furyk bogeyed the closing par-three 18th to slip back to a tie for second with McIlroy, but there was no doubt about the winner, who closed with a solid 68 for 11-under 269.
"He deserved it," McIlroy said. "He played the best golf this week."
American Chris Kirk, Justin Rose of England and Australian Jason Day were tied for fourth on seven-under.
Horschel's remarkable late season form has lifted him into golfing superstar status, but it has come too late to earn him a place in the United States team for Ryder Cup against Europe later this month.
"It's unbelievable," said Horschel, who missed the cut in the first FedEx play-off event before his incredible surge to the top of the standings from 60th at the start of the four tournament mini-series.
"But at the same time I knew my game was in the right shape and I just needed to get out of my own way, allow my golf game to show and it has showed in last three weeks."
His victory in the Tour Championship is worth $1.4m in prize money with a further $10m bonus for the FedEx Cup triumph, relegating Furyk to second place with McIlroy in third.
The trio had been among five men to have a chance of the bonus at the start of the week in Atlanta.
Horschel is also due for good news off the course as his wife Brittany is expected to give birth to a daughter by the end of the month.