The world champion needed all his renowned bike handling skills to first claw back a 40-second deficit and then hold off Koretzky in a barnstorming last-lap battle through the trees and rocks of the 4.4km Elancourt Hill circuit.
As they went wheel-to-wheel down a narrow descent, Pidcock chose a more aggressive line through the trees and the two riders almost came together with Koretzky losing momentum.
Pidcock then seized his chance, powering to victory in an epic race by nine seconds although boos rang out from the partisan French crowd as he crossed the line ahead of Koretzky and South Africa's Alan Hatherly who took the bronze.
"It's a shame because that's not really the spirit of the Olympics, but I do also understand, they're a passionate French crowd," an exhausted Pidcock said.
"But you know they didn't boo the rock that gave me a puncture did they," he said, referring to the misfortune that struck his bike on lap four
Asked about the last-lap manoeuvre that almost certainly won him the race, Pidcock said. "I did nothing wrong. He could have also gone left and I would have had to go right. In this position you don't hesitate. The gap was there so I was going."
Around 15,000 fans clambered all across a sun-baked circuit in the hills near Versailles again on Monday, hoping to witness more French gold. But Pidcock broke their hearts.
Road professional Pidcock, who abandoned this year's Tour de France because of COVID, looked strong early on as he attacked on lap three and only Koretzky could hold his wheel.
But calamity struck the Yorkshireman when his front tyre was punctured and he had to have a pit stop to change a wheel - Pidcock casually sipping from his water bottle as the mechanics frantically went about their work.
Once back in the race, Pidcock was well down but never panicked and relentlessly sliced into the deficit, before hitting the front on lap seven with Koretzky apparently tiring.
But the Frenchman was not done and he and Hatherly stayed with Pidcock as the bell went for a final tumultuous lap.
Huge roars erupted when Koretzky attacked first and gapped Pidcock but the Briton again responded before making his audacious move through the trees.
