The Ulsterman posted just a single bogey at Fanling where, in overcast and windy conditions, he ended the day outside the top 90.
The 23-year-old admits that he may have been lacking a little motivation after securing top spot in this season's Race to Dubai standings thanks to a top-three finish in Singapore last week.
He said: "I suppose after last week, and winning the Race to Dubai title, it was always going to be a bit of a let-down.
"I feel as though I am playing well enough but I just need to get my head and the golf to match up and I'll be OK.
"I just lacked a bit of energy out there, I felt a bit lethargic and mentally more than physically - if I am being honest.
"I bogeyed the first but then just got more frustrated as the round went on.
"I felt like I was hitting some decent shots and just not really converting any chances for birdies and I just let it go a little bit."
The early leader is world No 506 Spaniard Javier Colomo whose 64 required just 29 strokes for his second nine holes.
Tied-for-second is Colomo's 48-year-old compatriot Miguel Angel Jimenez who is a single shot adrift - and level with Aussie Andrew Dodt.
Jimenez, a two-time winner in Hong Kong, smirked: "I am like a good bottle of rioja because I just get better and better with age.
"I'm putting very well and it's a pity I missed a fairway on the ninth and then on the last got a big flyer.
"It's an old-fashioned course - not very long but you need to be very precise."