He waited and waited. He let the stage lead go away from him, he let the yellow jersey go, too, but finally on Thursday, with just three kilometres of the climb to Arcalis to run, Alberto Contador struck his first telling blow in the contest that really matters right now. He snapped his heels and left Lance Armstrong, his team-mate and rival, fading into the distance behind.

Armstrong could not respond. There are two weeks of this Tour de France to go, but the power of Contador’s break and Armstrong’s inability to give chase, let alone stay with him, are deeply significant.

Armstrong, the American seven-times Tour winner, had been waiting for this day. On Thursday, he called it his “big appointment” and in the morning, on his infamous Twitter feed, he said of the race and this first mountain stage: “It’s for real now.” He knew that Contador would test him and he knew also that, ten months after shaking the sports world with his comeback plan, this would be the true examination of whether he still had it.

But as Contador streaked away into the spectacular Andorra mountains, Armstrong could only toil on the wheel of Andy Schleck, his fellow chaser. The gap between the old master and his 26-year-old rival then simply stretched. Contador looked light in his pedals and Armstrong heavy. Contador somehow seemed to be smiling through the pain of his attack and 21 seconds after he had reached the finish, Armstrong followed him in.

It is not those 21 seconds that will split these two riders when they roll into Paris on July 26, but the psychological value of them. If Contador had any doubts before, they surely remain no longer. And if self-doubt is a concept that has ever found space in Armstrong’s mentality, now may be the time for it to discover a real home.

Up ahead of the two on Thursday, a different race altogether had taken place. A breakaway that was never caught was made by Brice Feillu, a 23-year-old Frenchman in his first year as a professional, riding for Agritubel. Three places behind him finished Rinaldo Nocentini, the Italian riding for the AG2R team — also in his first Tour — who takes the yellow jersey.

In the race for yellow, though, Nocentini is only six seconds ahead of Contador, a lead that the Spaniard will pick off when he feels the time is right. And Armstrong is only two seconds behind Contador, but it is not the time difference that counts. Thursday’s break by Contador was not to win the Tour, but to win control of his team.

The strange blurring of responsibility in the Astana team has left Armstrong and Contador uncomfortably side by side, with Contador as the nominal leader but the American the more influential member of the peloton and, by his own admission, in the race to win and not necessarily to serve.

Armstrong’s comments after yesterday’s stage were therefore lost on no one. “I’ve said all along, my obligation is to the team,” he said. But perhaps more significant was his analysis of Contador’s break. “It wasn’t really in the plan,” he said. “But I didn’t expect him to go with the plan. So I wasn’t surprised.” There was no comment on the fact that even though Contador may have broken any team agreement, when he did Armstrong was not able to stay with him.

Armstrong’s fingering of Contador as a selfish rider is not surprising. Of his own long-term chances, he said: “We’ll have plenty of days at the end of the Tour.” Indeed, it will be fascinating if Contador and Armstrong are still close as they go into the Alps in the final week. For while Thursday’s stage seemed to provide some meaty answers, it also asked questions. Most pertinently, if Contador was so strong, why did he not go any earlier? The decisiveness of his break was such that he could have gone with five or six kilometres left, not three, hitting his rival hard rather than with just a useful jab.

Given that they were so close to the finish, Armstrong would have known that while Contador was making a statement, it would not — in terms of seconds on the clock — be the difference between winning the Tour and finishing second. So there remains considerable intrigue. Armstrong has a habit of getting stronger throughout the Grand Tours, as he did notably in the Giro d’Italia two months ago. If he is still in touch with Contador by the Alps, maybe he will be strong enough to respond.

The closer this race gets to Paris, the more the Astana team are delivering a soap opera to replicate the classic Tour of 1986, when Greg LeMond and Bernard Hinault were team-mates in name and uniform, and little else. The previous year, LeMond had helped to deliver Hinault into Paris wearing the yellow jersey and the agreement was that the favour would be returned, though Hinault instead appeared more interested in attacking the lead rather than supporting it.

Armstrong can serve Contador now and help to take him to Paris wearing yellow. Or he can follow his nature and fight. No guessing which he will choose. “It’s ‘war’ in Astana” was the headline in Marca, the Spanish sports newspaper on Tuesday, after Armstrong had taken an early lead on Contador, and the story is that the young Spaniard elected to ride home that afternoon rather than travel with the team.

But after 220 kilometres yesterday, the longest stage of the Tour, the tables finally turned. It was a long, hard stage that came out of Barcelona and had hardly reached the city suburbs before a breakaway had formed. Christophe Riblon, the Frenchman, led the break slowly into the Pyrenees, through the biggest climb of the Tour so far, the Col de Serra-Seca, plunging down before the slow, spectacular climb to Arcalis. At the start of the climb, the break still had an eight-minute lead, but there was no panic in the peloton because there were no leaders among it that they feared. So they let the lead go and ended up fighting between themselves.

On the podium, the young Feillu was hugged by his brother and team-mate, Romain, and declared that the day they reach the Champs Élysées will be his birthday and he still hopes to be wearing the red polka-dot jersey for king of the mountains.

Also going well yesterday was Bradley Wiggins, the Briton who finished twelfth — in the same group as Armstrong — and now lies sixth overall. “My goal was top 20 in the GC [general classification],” he said, “and that remains the goal.” But while Wiggins tries to stay in touch with the leaders, we wait to see when Contador will look to put more distance between himself and the rest of them. Today and tomorrow are mountain stages with downhill finishes. There will be opportunities to lay another glove on Armstrong. We await the killer blow.