Gareth Maybin got off to a fantastic start at the Volvo China Open by posting a seven-under par 65 to sit just one shot off the pace after the opening day’s play.
Rookie Chang-won Han shot an eight-under-par 64 at the Luxehill International Country Club in Chengdu to lead a five-man group, including Maybin, by one.
Padraig Harrington bogeyed the 10th and seventh holes en route to a one-under 71, while the other five Irish golfers competing all hit under-par scores.
Paul McGinley and Peter Lawrie shot four under, while Shane Lowry also impressed with a three-under 69.
Damien McGrane and Michael Hoey are yet to finish their opening round after playing 16 and 14 holes respectively. Both players were two under par when the opening day’s play was halted due to poor light.
The South Korean, Han, started brightly on the 10th with two birdies and picked up further shots on the first and fourth.
He then picked things up in style with four successive birdies down the stretch to go home in 30 and leap up the leaderboard.
Among those a shot further back are England's James Morrison, Wales' Bradley Dredge and Dane Soren Kjeldsen. Keith Horne of South Africa was also seven under but with four to play after bad light prevented him finishing.
Han, 19, is in his maiden professional campaign and seems to be handling it well.
‘It's very good weather and I got a bit lucky today,’ he admitted. ‘I missed a few easy shots but most of the time I was perfect and hit the fairways and got close to the pins.
‘I felt comfortable going into those last four holes which I birdied. I didn't really feel any pressure and it was a good finish.
‘I've been playing golf for nine years. I've only been professional from this year. I play for the national team.
‘I've not made much money yet as a professional so it would be nice to get some this week!’
Morrison is gunning for a second win on the European Tour and said: ‘My strengths are driving it straight, short irons and chipping and putting which is this golf course all over.
‘So before I even got here and playing Tuesday morning I thought I like this place but it's hard not to get ahead of yourself.’
Former US Open champion Michael Campbell was three off the lead following a five-under 67.
The Kiwi, who has struggled in the last two years with injury, has put a run together recently having previously made only four cuts in two years.
Campbell, who finished 35th in Malaysia recently, said: ‘Every week seems to be getting better for me.
‘I didn't finish it off last week in Malaysia but today I played great from tee to green and putted better.
‘I missed a few short ones coming in but beside that it was a real solid first round. It's a snowball effect. I'm growing in confidence with each shot, each putt, each chip.
‘You ask any athlete - confidence is not something you can buy from the corner store. You have to earn it.’
Sergio Garcia was solid throughout with a bogey-free six-under 66 to be among a group sharing seventh, with Scotland's Richie Ramsay joining him.
Defending champion YE Yang is four off the lead.
