Ireland's Paul Dunne shines in elite company at WGC event in Shanghai
US Open champion Brooks Koepka felt "destiny" was on his side after firing an eventful 64 to claim the lead in the WGC-HSBC Champions in Shanghai.
Koepka carded seven birdies, an eagle and a solitary bogey at Sheshan International to finish eight under par, a shot ahead of Thailand's Kiradech Aphibarnrat and Malaysia's Gavin Green.
American Ryder Cup star Patrick Reed and South Africa's Haydn Porteous were two shots off the pace on six under, with Olympic champion Justin Rose and Ireland's Paul Dunne part of a five-strong group on five under.
Koepka began his round on the back nine and birdied the 14th, 16th and 17th before holing from 20 feet for eagle on the par-five 18th to reach the turn in 31.
The 27-year-old also birdied the first before three-putting the third, but bounced back to pick up shots on the fourth, seventh and eighth, the latter coming in unlikely fashion.
"It was an interesting hole to say the least," Koepka told reporters after his round. "It was an awful 3-iron (off the tee), hit it in the water and was lucky enough or fortunate enough to at least be able to hit it and advance it.
"And then to hit 3-wood in there to 15 feet and then make the putt, we were laughing. It was almost kind of like destiny to make that putt for how lucky we were that whole hole."
Koepka, whose shirt bore the evidence of his escape from the muddy water, added: "I thought we played really well. Putted very well. One little hiccup and three-putted from about four feet.
"I felt like I started really well. Drove it really well. Any time you're making putts and you're keeping it in the fairway, you're going to shoot good (scores)."
Green, who won the Taiwan Masters on the Asian Tour at the start of the month, carded seven birdies in a bogey-free round, while Aphibarnrat recorded 10 birdies and three bogeys.
"It's my first time here and it's obviously my first WGC," Green said. "The last couple of weeks, playing on the PGA TOUR, it's a big difference for me. It takes a little getting used to.
"It's changed me a little bit. I've been trying to push for it, obviously, and it's not coming out the way I wanted to.
"So I'm taking a different approach this time and am just going to try and enjoy my first WGC. Dad's on the bag, so we're just going to enjoy it and sticking to the game plan. If things get out of hand, we try to get back in play and we try to wedge it close."
Dunne is also playing his first World Golf Championships event in the wake of claiming his maiden European Tour title in the British Masters earlier this month.
The 24-year-old, who came to prominence when sharing the 54-hole lead in the 2015 Open while still an amateur, carded six birdies and a solitary bogey on the 17th, where he three-putted from close range.
England's Tyrrell Hatton, who is seeking a hat-trick of victories after winning the Dunhill Links and Italian Open, is four shots off the pace after a 68 matched by compatriots Matt Fitzpatrick and Matthew Southgate and world number one Dustin Johnson.
Race to Dubai leader Tommy Fleetwood carded an opening 71, but defending champion Hideki Matusyama struggled to a two-over-par 74.