Northern Ireland’s Rory McIlroy became the first player to win the FedEx Cup three times after success on Sunday in the PGA’s Tour Championship.

The 33-year-old overturned a six-shot lead by Scottie Scheffler to finish one clear of the American and Sungjae Im.

Four-time major winner McIlroy carded a four-under-par 66 in the final round to finish on 21 under.

The Northern Irishman receives $18m (£15.36m) in prize money after his fifth victory of the season.

“What a week, what a day,” McIlroy told Sky Sports.

“I feel like Scottie deserves at least half of this. He’s a hell of a competitor. It was an honour to battle with him.”

Scheffler started the week with a six-shot advantage over McIlroy as players began the season-ending event on different scores determined by their place in the FedEx Cup standings.

After a suspension of play during Saturday’s third round because of lightning, world number one Scheffler led by just one when play resumed on Sunday morning but extended his lead to six before the final round.

When the final round began later on Sunday, the pair both bogeyed the first hole but Scheffler dropped shots on the fourth and sixth, while McIlroy birdied the third and made three more in succession from the fifth.

A poor bunker shot from Scheffler on the 18th meant the Masters champion was forced to scramble for a par to tie for second with South Korea’s Im, who equalled McIlroy’s final-round 66.

“I didn’t really give myself much of a chance teeing off today, I thought six behind was going to be really tough to make up but my good play and Scottie’s not-so-great play meant it was a ball game going into the back nine,” McIlroy added.

McIlroy has been one of the PGA Tour’s most vocal advocates during golf’s ongoing power struggle, and was one of the leading voices in a meeting held earlier this month by the tour’s top players to discuss the threat of LIV Golf.

Following his triumph, he said: “I believe in the game of golf, I believe in this Tour in particular, I believe in the players on this Tour.

“It’s the greatest place in the world to play golf, bar none, and I’ve played all over the world.

“This is an incredibly proud moment for me, but it should also be an incredibly proud moment for the PGA Tour. They have had some hard times this year but we are getting through it and that was a spectacle out there today.

“Two of the best players in the world going head-to-head for the biggest prize on the PGA Tour and I hope everyone at home enjoyed that.”

McIlroy said the FedEx Cup victory would help “soften the blow” after he failed to win the 150th Open Championship where he shared the lead after 54 holes, but ultimately finished third behind Australia’s Cameron Smith.

“St Andrews was really hard for me. It was a tough one to get over,” he said.

“This softens the blow a little bit. It doesn’t make it that much easier to get over, but it’s great to end the season on a high note like this.”