It looked as if reigning Macau Grand Prix winner Leong was going to have an easy time of the eight-lap opener when closest rival Chang rolled to a stop at the end of the warm-up lap. The issue for Chang was a gear selection problem, the Macao driver forced to restart his car before lining up on the grid.
The mishap meant that instead of starting second behind Leong, Chang had to start at the very back of the field. But it didn't prove to be a significant advantage for Leong, thanks to a remarkable first lap from Chang. He managed to work his way to third as he crossed the line to start Lap 2, before sweeping past Li Si Cheng to grab second before Lisboa.
Chang then set after Leong, cutting the five-second gap down to just over 3s on the next lap. But the frantic start to the race took its toll, Chang's car left sporting damage to its front wing.
Leong responded to Chang's charge over the following laps, building the gap up to just over 7s. He then managed his lead to the finish, his winning margin over Chang 5.4s as the pair secured the front row for tomorrow's 12-lap SJM Formula 4 Macau Grand Prix Race 2.
"When I saw that I had a gap at the start, I was trying to slow down the pace a bit," said Leong. "But I realized that you can't do that, because you're always next to the wall. You still have to focus. I couldn't relax, so I decided to get back into a rhythm. I was pushing a little bit. It was hard.
"I saw [Chang] was catching up, so I thought, 'okay, I need to push a bit more'. That's when I realised I couldn't relax too much. When you relax at this track, the pace is so different.
"Tomorrow the start will be very important. Hopefully I get a good start and I don't give Andy a tow. Let's see what happens tomorrow."
Chang added: "I had a gear problem [on the formation lap], I couldn't get into first gear. I switched off the engine and then put the steering out to get the sensor to work again. And then I could get first gear.
"It was a tough race. I don't know how many cars I overtook. I was trying to catch Charles but he was way too quick. Second is good for me for tomorrow. I can have another go at winning."
Li finished a lonely third ahead of Jing Ze Feng, who put in a good drive from back in the field to grab fourth.
The battle for fifth was a tight one, Shang Zong Yi chasing down Li Chao before getting past through Mandarin at the start of the final lap.
Mak Ka Lok finished seventh ahead of Lyu Jing Xi, Lin Li Feng and Wong Yiu Ming.