Justin Thomas faltered in the final round at the BMW Championship on Sunday but held on for an ultimately comfortable three-stroke victory at Medinah in suburban Chicago.
He carded a closing four-under 68 to finish on a 25-under-par total of 263, while fellow American Patrick Cantlay shot a 65 for second place on 22-under.
Thomas started the day with a six-shot advantage but when he bogeyed the 10th hole, after almost hitting his second out of bounds, the lead over Cantlay was down to two.
But Thomas steadied with clutch play over the next three holes, twice holing putts of around 12 feet to re-establish his authority.
"Patrick made that very interesting," a relieved Thomas said.
"I hit the ball so bad to start the day. I made it hard on myself because usually I'm pretty good at hitting fairways and greens and I couldn't hit a fairway ... but I stayed patient and that birdie on 11 was huge.
"I was really nervous today. It's hard to play with the lead. I was enjoying it, though."
The victory was the 10th of his PGA Tour career but the first this year in what has been an injury-interrupted season. Thomas hurt his wrist in March and took six weeks off to rest.
"I'd forgotten how hard it was to win," said the 26-year-old former world number one.
"This game is so hard, you don't know how often things like this are going to happen.
"It's not like I've been playing bad. I would argue I've played just as well this year as any other year. It's a very humbling and tough game and I learned to respect it and be patient."
The result means Thomas is the number one seed at next week's season-ending Tour Championship in Atlanta.
The top 30 players on the PGA Tour's FedEx Cup points list qualified for the event, where the winner at East Lake will collect $15 million.
For the first time the tournament will use a staggered start based on players' position in the points race, with Thomas starting at 10-under-par.
The qualifiers ranked 26th to 30th will begin at even par.
Three players who started the BMW Championship outside the top 30 in the standings snuck into the Tour Championship -- Japan's Hideki Matsuyama and Americans Lucas Glover and Jason Kokrak.
Matsuyama has never missed a Tour Championship since joining the tour in 2014.
Missing out was Ireland's British Open champion Shane Lowry, along with Americans Andrew Putnam and Harold Varner III.
There will be no defending champion at East Lake, as Tiger Woods did not qualify after finishing equal 37th on Sunday.
(Reporting by Andrew Both in Cary, North Carolina; editing by Tony Lawrence/Peter Rutherford)
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