But on Sunday at the WGC-Mexico Championship, Johnson was reminded that his 20 PGA Tour victory is a requirement for lifetime membership.
Third-round leader Aaron Baddeley shot a 72 to tie for second with Daniel Berger (66), Roger Sloan (67) and Johnson Wagner (69). But the lead cut in half after three holes, and Johnson escaped potential trouble on the fifth when he was given free relief behind a tree because the heel of his shoe was on the cart path.
It was McIlroy's fourth top-five finish in a row and a $1.095m pay cheque, but it was a forgettable week for Shane Lowry who made three birdies, two bogeys, a double and a triple bogey in four-over 75 as he slipped to tied 62nd on nine-over, winning $50,500. He bogeyed the hole, Johnson birdied it, and it was all but game, set and match.
The American recorded five birdies in seven holes in a final-round 66 as he collected his 20th PGA Tour win and sixth World Golf Championship crown. He left Sunday night with his 20th career PGA Tour victory, his sixth World Golf Championship and now wonders how far that will take him. Here Johnson's troubles continued, as his tee shot finished right up against a tree.
But McIlroy missed a six-footer for par after the fourth to go three behind and two holes later, fatally found himself five adrift after his own mistakes, and key decisions by European Tour rules official Mike Stewart, proved enough to derail his title charge. He won the championship two years ago when the tournament moved here, and he finished in a tie for seventh last year.
Paul Casey of England carded a second straight 65 to wind up 10 shots behind in a tie for third with Kiradech Aphibarnrat of Thailand and Ian Poulter of England, who both finished at 68.More news: Nokia 6.1 Plus with 6GB RAM is Now Official
"There's too many important tournaments coming up", Johnson said. "I managed do it today and that's just incredible".
He won the Saudi International earlier this month and he will return to No.1 in the world next week.
Cape Town - Tiger Woods' putter went cold in spectacular fashion when he four-putted during the third round of the WGC-Mexico Championship on Saturday.
"I was honestly very nervous, especially last three holes, " said Yang, who also won the event in 2015 and 2017.
PGA TOUR: In Rio Grande, Puerto Rico, Martin Trainer closed with a 5-under 67 to win the Puerto Rico Open for his first PGA Tour title, a three-stroke victory over four players. "I'm not frustrated because it seems like I can only do what I can do, and I can only control me".