The Australian's grim-faced determination as she launches herself across the 10 hurdles is familiar to fans of athletics all over the world and it has always been the same, according to her coach Sharon Hannan.
"She was always committed, always wanted to be very, very good at this chosen sport," Hannan told Reuters during preparations for the London games.
"So she's really been very easy to coach from that perspective. She never, never misses training, preparation is a priority to her ... a big priority.
"She has an absolute commitment to herself. This is what she wants to do, she wants to be the best in the world. She asks me 'Sharon what will I have to do to do it', and then she does it."
Hannan started coaching Pearson in Queensland when she was 12-year-old Sally McLellan back in the late-1990s.
A talented sprinter with natural speed who also still runs the 100 and 200 metres flat, Pearson did not decide to focus on the hurdles until five years ago.
"In 2007, we went to the world championships still not really knowing," said Hannan "I said to her she still wasn't in a position where she wanted to make a choice yet. She made semi-finals in the hurdles and the 100, she was only 20.
"Then she worked out she was ranked higher in the world in the hurdles, so she decided to choose that for a bit.
"We've never ruled out doubling up again in the future at some stage but certainly not at the these Olympic Games," she laughed.
Olympic silver followed in Beijing in 2008 and she backed that up by claiming the world title in Daegu last year, when she lost just one race.
Hannan laughs when asked whether their relationship was more like that of a mother and daughter or teacher and pupil.
"I suppose if you had the same teacher for your whole school life it would be something like that," she said.
"I bring the technical side, she brings the body."
This year, Pearson has also lost just once, in her final outing before the Games at the London Grand Prix, and there was certainly the air of the teacher in Hannan's explanation for it.
"She made a slight error of judgement, it won't happen again," she said curtly.
On Monday, Pearson qualified for the semi-finals in 12.57 seconds, the fastest time ever in the first round at an Olympics.
"Once she's on the track, it's pure business, she's very focused, she's determined to be the best she can be in that race," Hannan said.
"I remember a few years ago, I said to Sal, 'take the heat easy, save yourself. She said, 'how do I do that?'" With Pearson in such good form, there have been suggestions that she might be able to break Yordanka Donkova's 24-year-old world record of 12.21 in London.
"If we had a nice little tailwind, then?" Hannan shrugged. "She's in good shape, anything's possible.
"We didn't come here expecting to break any world records, the focus hasn't been on any sort of time at all. The time will be whatever it takes to win a gold medal."