At a mere 900 feet, the third category climb of the Cote des Forges is a mere pimple compared with next week's Alpine and Pyrenean passes, yet the drag over its wooded summit provided a brief vignette of what may await this Tour.
A group of a dozen drew ahead of the main field, including last year's top four: Lance Armstrong, Jan Ullrich, Joseba Beloki, and Christophe Moreau, and the 2000 King of the Mountains Santiago Botero.
All the favourites, in other words. They observed each other briefly, as if making sure that the magic circle was complete, and then permitted the rest of the front-runners to catch up again before battle was engaged for the stage finish, which went, for the second time in three days, to Ullrich's team-mate Erik Zabel.
Small the Forges may be, but its one-in-eight slopes are steeped in cycling history, a fixture in the oldest one-day Classic on the calendar, Liege-Bastogne-Liege. The last time the Tour tackled these roads, in 1995, it was the launch pad for one of the greatest coups of Miguel Indurain's five Tour wins, the daring surprise attack into Liege which effectively won him his fifth Tour.
This time round, the drama was on a lesser scale. The Forges, and the other two ascents in the Ardennes triptych, the Mont Theux and the Cote de Sart-Tilman did see off the the only Italian hope, Francesco Casagrande, the runner-up in last year's Tour of Italy. Out of sorts due to illness before the Tour, he finished almost five minutes behind and is talking of returning to his native Tuscany.
The maillot jaune Marc Wauters was equally ill at ease once the race left the flatlands of Limbourg and crossed the river Meuse into the steep wooded valleys of the Ardennes, and the Australian Stuart O'Grady duly benefited.
On Monday in Antwerp he and his Credit Agricole team, led last year by Chris Boardman, had completely failed to realise that Wauters was in contention for the yellow jersey. Blindly, they let the Belgian slip away in the last kilometre, a howler which O'Grady described as being "like missing the winning penalty in a World Cup final".
After a sleepless night, normal Australian sporting business was resumed yesterday. O'Grady's team-mates set a searing pace once they realised that Wauters had been left behind, handing them a second chance to the race lead.O'Grady now has 17 seconds in hand over Moreau, which should be sufficient to keep him in yellow at least until tomorrow's team time trial.
Zabel was always the likely favourite for the stage as none of the other sprinters made it over the hills in the front group of 100, and he is a past master at a finish like yesterday's, at the top of a lengthy drag.
There was much speculation at the start of this Tour about his relations, or lack of them, with Ullrich, who specified that the team selection should include specialist climbers to help him in the mountains, at the expense of the two men who assist Zabel in his sprints. Sunday's victory at Boulogne reconciled them, and yesterday in the last kilometre Ullrich was never far from the Berliner, who was at pains to point out afterwards "the team did very good work; the atmosphere is very good".
When he launched his winning effort, on his shoulder was Armstrong, no less, who was acutely aware that vital seconds can be won and lost in an uphill finish like yesterday's if even a small gap appear between the riders in the group. Ullrich and Beloki were equally determined to give nothing away, and finished 13th and 14th to the American's 10th.
At the other end of affairs, David Millar slipped yesterday to the position of "lanterne rouge", the name given to the rider who is last in the overall standings, even though he had his best stage of the race so far.
He is the first Briton to hold the honorary title since 1985, but remains optimistic.