Every decade or so you get an epic Tour de France stage that is recalled in every detail in perpetuity and Andy Schleck's staggering 60km attack yesterday on two of the toughest mountain climbs in the Alps was precisely that.
Appropriately enough, Schleck was watched every inch of the way by the greatest escape artist of them all, Eddie Merckx, who was the VIP guest of the day in the race director's car which tracks the leaders.
A smiling Merckx, leaning out of the roof hatch, could be seen roaring encouragement to Schleck as the Luxembourg rider, who can sometimes appear to laid back and diffident, bared his claws and ripped the race apart, causing mayhem behind him.
"What Andy Schleck did today was really something, to break from so far out, I really appreciate that," purred five-time Tour winner Merckx. "He rode with great courage, gave a cycling lesson to everybody."
Schleck eventually won the stage from his older brother Frank by 2min 07sec, blew the challenge of Alberto Contador apart and closed to within 15 seconds of yellow jersey holder Thomas Voeckler. It was a virtuoso, probably career-defining effort.
Voeckler, meanwhile, produced yet another courageous ride as France totters on the brink of a collective nervous breakdown at the prospect of its first Tour winner since 1985.
The bookies still make him no better than 14/1, with Andy Schleck now evens, but Voeckler has been defying the odds since the race entered the Pyrenees last Thursday.
Andy Schleck always fancied going to war yesterday and he cold-bloodedly picked his battle ground halfway up the epic Col d'Izoard climb, way too early for the many roadside 'experts'.
But for the first time on this Tour, Schleck accelerated without a backward glance. No hesitation or waiting to get the nod from Frank, no second thoughts. This was it.
Behind him, Contador, his nemesis last year, had been blown to the winds finishing 3min 50sec adrift. It was a brilliant coup.
In fact it was more heist than a coup. This was daylight robbery. The select group were stunned and an abject sense of despondency and hubris seemed to settle over them.
Eventually it was Cadel Evans who stirred himself some 13km from the top of the Galibier and set out to try to recoup some of Schleck's 4min 24sec lead.
Evans, who got precious little help, was remorseless and worked like a dog to contain his losses and will be pleased enough finishing just 2min 7sec down. He now trails Andy by 57 seconds and as the best time-triallist of the contenders remains very much in the hunt.
Nicolas Roche moved up two places to 19th overall after a brave effort as part of Schleck's break (© Daily Telegraph, London)