The moment of truth for Zhen Wang came when he glanced at the disqualification board in the final throes of the men’s 20km.
The Chinese could see the man alongside him was dancing with danger after Russia’s Andrey Krivov had posted two DQs on the huge screen.
It was the perfect platform for Wang to mount a second sprint having already moved into the lead shortly after the halfway point.
As tired as Wang was, he knew his adversary either had to risk a final card that would eliminate him if he gave chase, or hold back knowing silver was better than the sidelines.
It still meant the Chinese, not 21 until August, had to find the reserves to kill off the final threat to gold – and his country’s successful defence of the individual title won in 2010.
By the time he grabbed the customary national flag yards from the finish in celebration, Krivov was 14 seconds back, and the gap to third was even greater.
Making his 20km debut for the year was the man who set the World record on the streets of Saransk in 2007. This time, Vladimir Kanaykin gave valiant chase to do better than bronze, but was likewise isolated after he crossed the line.
Another surprise in a weekend where the hosts were expected to sweep all before them was a last charge for the line by Ukrainian Rusian Dmytrenko.
The blue and yellow vests of Russia’s neighbours had been prominent in the opening laps, but no-one expected Dmytrenko to edge past Sergey Morozov at the end in a battle for fourth.
It was to lead to a second bronze team medal for Ukraine. But as delighted as Dmytrenko and co must have been, Valeriy Borchin had a cap pulled firmly down on his head at the ceremony as if to mask a bad day at the office.
Sure, Russia had duly taken the top tier on the podium, but the Olympic and IAAF World champion never looked comfortable, and had to settle for a distant 10th – a big shock.
The results showed 'season’s best’ against his name, but only because it was Borchin’s first 20km of the year, and 1:21:29 was more than three minutes slower than his best.
Earlier, the usual throng of thirty or more passed 4km in 16:29, but that was the signal to up the pace and rattle off a straight four-minutes for the next 1,000m.
Challenges from Ireland’s Robbie Heffernan, Isamu Fujisawa from Japan and Erick Barrondo eventually bit the dust – but at least the latter was up there until the judges removed him at 12km.
The Guatemalan had a fantastic 1:18:25 from March to back up his claims for a medal, but once he was gone it came down to a straight duel with Wang standing tallest at the end.
China collected team silvers to join Russia and Ukraine on the podium.
Wang paid tribute to coach Sandro Damilano – brother of Maurizio, the former IAAF World champion.
The Chinese said: "I did not expect to win as Russia was on home soil. At 16km, I thought there was a chance, and it was only at the end I realised I was in the lead by a distance.
"Damilano is a great coach and I have followed him for two years."
The Russian silver medallist was just as pleased.
Krivov said: "It may be just silver – but it was platinum to me, because I can now go to London and the Olympics." "The DQ cards had no influence on the way I walked. Maybe, it was a good thing I did not know much about them."
Kanaykin admitted hometown pressure had been a factor. "It was a big responsibility to be here and perform in front of so many supporters," he said.
"I won’t know until my next race in June whether I’m going to the Olympics."