Deposed Masters champion Bubba Watson had to settle for an opening-day 70 to sit four shots off Huang Wen-Yi's lead at the Shenzhen International.

Watson, who finished 38th at Augusta National on Sunday as the defence of his Masters crown finished in disappointing fashion, was struggling on one over after 13 holes on Thursday - having started on the back nine - but three successive birdies got him back under par.

The American's 70 leaves him in joint 17th place, with home hope Huang setting the early running on a day when he shared the highlights with An Byeong-hun, who recorded a hole in one.

Damien McGrane was best of the Irish with a one over par 73, one shot ahead of Peter Lawrie, Kevin Phelan and Michael Hoey.

China's Huang, who only started playing at the age of 22 some 12 years ago, carded eight birdies and two bogeys in his six-under-par round as he finished the first day one clear of a group of four players.

Among them are American Peter Uihlein after he completed the final 10 holes at Genzon Golf Club in six under par, and South Korea's Byeong, whose ace came on the 226-yard eighth - his penultimate hole - as he finished birdie-par-eagle-birdie.

Also in the that chasing pack on five under are Chile's Felipe Aguilar and Thailand's Kiradech Aphibarnrat.

Huang, who worked as a labourer on construction sites before taking up the sport, said on "Last year I played very bad.

"This year I have changed my swing and yesterday I changed the driver and I like the new driver. I like the course; the green speed is very good."

South Africa's Darren Fichardt is on his own at four under, with the leading Europeans coming in a group of 10 players at three under which includes English quartet Ross Fisher, Anthony Wall, Matt Ford and Andy Sullivan,