The New Zealanders, ranked Nos 1 and 5 in their respective classes, rode to form at the Laoshan Moto Cross venue yesterday.
For Walker, the heat really goes on today as she has her first bodily contact with the 15 other riders striving to muscle their way to the sport's maiden Olympic gold.
While two of her keenest rivals pranged during the solo time trials, Walker twice covered the course almost error-free to earn a plumb gate posse for her three semifinal races starting from 1pm today (NZT).
The men's and women's one-off medal races start from 2.30pm (NZT).
World champion Shanaze Reade and French top qualifier Anne-Caroline Chausson both lost their poise and concentration during their seeding laps -- though both still managed to record faster times than the cautious 20-year-old from Kawerau.
Walker had the fourth fastest time though, as she pointed out before racing, the stopwatch was generally irrelevant.
"The time trial results won't be the same as the racing results," she said.
"There's an American guy who wins 80 per cent of the T-Ts, he's never made a final -- that's an example of BMX."
BMX is also about collisions and if the International Olympic Committee (IOC) deigned to include it to appeal to the X-Games generation, it appears a masterstroke.
There were crashes galore during the scene setter, and once the women's competition turns physical more chaos is assured.
Willers had one tumble as the men's field was reduced from 32 to 16 by three quarterfinal runs.
Fortunately for the 22-year-old from Cambridge, his accident after being clipped from behind during the first quarterfinal was at the lower end of the severity scale.
He was able to dust himself off and still finish fourth. Two canny rides allowed him to book third and second placings to have him seeded second in his eight-strong semifinal line-up.
Willers trailed Mike Day in his semifinal rankings after the American enjoyed a flawless morning -- winning each of his quarters.
"Not to sound too cocky, but everything's kind of coming naturally."
But as any BMX rider knows, gold can turn to dust on the first turn.
Three-time world champion Kyle Bennett of the United States was caught up in a crash in the third run of the quarterfinals and didn't complete the course, though he had enough points from the previous two runs to make the cut.
The biggest name to fall was Australian Luke Madill, who got caught up in a melee in the second run and finished last.
Reade had no explanation for her mangling of the first turn after analysing it with coach Grant White, the Australian who used to mentor Walker.
"I don't know what happened. We looked at the videos and it's just one of those things," she said.
Chausson, her clothing ripped and dirty, blamed nerves for her uncharacteristic error on the home straight.
"All the girls are so motivated because it's the first Olympics for BMX," she said.
"It's all I've been thinking about for years."
BikeNZ high performance manager Mark Elliot said the miscalculations by Reade and Chausson were indicative of the anxiety brought on by the high stakes.
"It just shows the Olympic pressure," he said.
