The Craft-Bamboo Mercedes driver came into the eight-lap qualifying race as the man to beat, having topped every session of the weekend so far.
He looked every bit the favourite in the early stages, too, holding off TORO Racing Mercedes driver Ye Hongli on the run to Lisboa before sprinting to a seven-tenths lead on the opening lap.
His progress was swiftly halted thanks to Eric Kwong Hoi Fung (KiddyWorld Racing Mercedes) hitting the wall in the Solitude Esses, triggering a lengthy safety car.
It was during the caution that the greatest threat to O'Young's lead emerged, race officials investigating his start for a possible infringement.
He was subsequently cleared of any wrongdoing.
The race went green again to start Lap 5, fading light forcing race officials to declare that the final tour.
That made for an easy run home for O'Young, his winning margin just over three seconds over Ye.
"The team has really worked hard in preparation," said O'Young.
"This is a very different year, so everything is happening a lot remotely. It was also a very short time to plan everything, so we had to work hard on quick thinking, having a lot of meetings and strategies. So I'm glad we're here.
"And it's probably the first time I've driven at night in Macau..."
It was an Audi three-four behind the lead Mercedes, Chen Weian (Audi Sport Asia Team TSRT) ahead of Marchy Lee Ying Kin (Audi Sport Asia Team X Works).
Lee had come under some early pressure from Toro Racing Mercedes driver of Min Heng on the opening lap, but managed to hold on to fourth.
Heng came home fifth ahead of teammate Zang Kan, while Lo Kai Fung (ZUVER Audi) was the best of the Macanese drivers in seventh.
Bei Siling (GRID Motorsport Lamborghini) finished eighth, Liu Lic Ka (Craft-Bamboo Mercedes) ninth and Yao Liagnbo (T.K.R Mercedes) in 10th.
Chris Chia On will start the main race as the best GT4 driver after finishing 11th outright in his PHANTOM PRO Racing Mercedes.