The Masters champion, making his first appearance since the Ryder Cup, carded eight birdies in his blemish-free round at Sheshan International.

Fellow Americans Xander Schauffele and Tony Finau ended in a tie for second on six under with England's Matt Fitzpatrick a shot further back.

Tommy Fleetwood was in a group of five on four under while defending champion Justin Rose was on three under along with Ian Poulter and Matt Wallace.

Adam Scott is also in the top 10 after shooting a three-under-par 69 in his opening round, including a near eagle on the first hole.

Fellow Queenslander Jason Day finished two shots back, while Adam Bland was on even-par 72 after his three bogeys were cancelled out by a late trio of birdies.

Rory McIlroy also finished on level-par 72 – alongside new World No.1 Brooks Koepka – after battling to cancel out a double bogey and two bogeys with four birdies.

Reed, playing the back nine first, started superbly with birdies at the 11th and 12th and picked up two more shots before a run of three successive birdies after the turn saw him power ahead. He added another birdie on the 9th, his last.

RIGHT: Scott (T10) is the best-placed Australian after the opening round in Shanghai. PHOTO: Andrew Redington/Getty Images.

The American told "It felt really good because if you can go out and shoot rounds like that in these kind of conditions, you know you're going to have confidence when the wind dies down and there are perfect conditions out there.

"I really just need to keep on taking it day by day and try to shoot the lowest round I can each day. Hopefully I'll shoot a couple more of these rounds, I think that will help me out."

Schauffele's 66, which came on his 25th birthday, also did not feature a dropped shot while Finau's card included one bogey and seven birdies. Fitzpatrick recovered well to shoot 67 after two bogeys in his opening four holes.

West Australian Brett Rumford finished on one-over-par 73 after a chequered run of birdies and bogeys, while Jason Norris carded a similarly frustrating 74.

Former World No.1 Dustin Johnson laboured to a two-over-par 74, while West Australian Jason Scrivener finished the round with a more forgettable 75.

Champion Golfer of the Year Francesco Molinari and Queenslander Cameron Smith both struggled and finished on 76.