Brooks Koepka fired a brilliant opening 64 to take a one-shot lead after day one of the WGC-HSBC Champions but had a host of European Tour stars chasing him down at Sheshan International Golf Club.
The US Open champion carded an eagle and seven birdies on his way to an eight under total to sit a shot ahead of Thai Kiradech Aphibarnrat and Malaysia's Gavin Green.
Haydn Porteous and Patrick Reed were then at six under, a shot clear of Paul Dunne, Justin Rose, Ashun Wu, Tony Finau and Matt Kuchar.
Koepka had his professional breakout on the Challenge Tour, winning three events in 2013 before going on to win twice on the European Tour, including that victory at Erin Hills in June.
The American parred his first four holes but then made three birdies in his next four and an eagle on the 18th meant he turned in 31.
Another birdie on the first followed but he three-putted the third from inside six feet before picking the shot straight back up after an excellent tee-shot.
A nice approach to the seventh brought another birdie and despite finding water off the tee on the eighth, Koepka hit a marvellous third just over the back of the green with a three wood and holed a birdie putt to take the solo lead.
"I felt like I played really well," he said. "I drove it pretty well and putted extremely well except for one little hiccup.
"You've got to get off to a good start. Doesn't really mean much - three other days - but any time you can get off to a good start and be close to the lead or have the lead, that's what you want. Just roll into that the rest of the week."
Aphibarnrat bogeyed the 11th but made back-to-back birdies on the 13th and 14th before dropping back to level par with a bogey on the next. A hat-trick of gains from the 16th then moved him to the summit.
He did not stop there, hitting an excellent approach into the first and getting on the green at the par five second in two to get to five under. An eight-foot putt on the third handed him the solo lead and when he holed a monster on the fourth it was seven birdies in a row and he was absolutely flying.
A three-putt from just off the green at the next then led to a third bogey of the day and made it 11 holes without a par. A pair of pars did eventually follow but an 18-footer on the eighth brought a tenth birdie of the day.
"It's a good momentum," he said. "Just keep playing well the last couple weeks in Europe and, to be honest, shooting seven under, opening round in the World Golf Championships, there's a lot of top players in the field. It's just a fantastic start and I want to keep the momentum.
"It's all about putting. I didn't hit the ball well. I didn't bring my A-game out today but my putting is fantastic. I holed almost every putt on the greens."
Green was bogey-free in his impressive opening effort, making birdies on the second, fourth, eighth, tenth, 13th, 16th and last.
South African Porteous had five birdies and two bogeys on the front nine and made further gains on the 11th and 12th. A double-bogey seven on the 14th stalled his momentum but he birdied the next two and the last in a 66.
A big finish helped American Reed to six under as he made gains on the 14th, 18th, second, seventh, eighth and ninth.
Birdies on the second, fifth, sixth, 11th, 13th and 14th had Dunne going well but the Irishman dropped a shot on the 17th, while England's Rose also made six birdies and a single bogey.
Home favourite Wu was blemish-free with gains on the second, fourth, fifth, 14th and 16th.
Rafa Cabrera Bello, Matthew Fitzpatrick, Tyrrell Hatton, Matthew Southgate and Henrik Stenson were then in the group at four under.
Bernd Wiesberger already has a win in China this year and he made the 32nd hole-in-one of the 2017 season on the fourth. The Austrian sank a seven iron from 167 yards for the 1,002nd ace in European Tour history.
