LE PUY-EN-VELAY, France — The battle for victory will go down to the wire at the Tour de France.
With just six stages left before the three-week race reaches the Champs-Elysees, only 29 seconds separate the top four riders in the general classification.
Defending champion and three-time winner Chris Froome has an 18-second lead over Fabio Aru of Italy. Frenchman Romain Bardet, the runner-up to Froome last year, is 23 seconds back from the leader, in third place. In fourth, is Colombian Rigoberto Uran.
It’s an unusual situation ahead of an intense final week of racing that includes two Alpine stages in high altitude and a short time trial.
‘‘It’s the hardest fought battle in terms of Tours de France I’ve done before,’’ Froome said during Monday’s rest day. ‘‘I’m just grateful I’m on the right side of those gaps.’’
Froome has the strongest team and remains the favorite to win in Paris, despite some rare signs of weakness.
He endured a bad day in the Pyrenees during a grueling stage to the ski station of Peyragudes, when he lost the overall lead to Aru after wearing the race leader’s yellow jersey for seven days. But the Team Sky leader recovered in style two days later, when Aru was trapped at the back of the peloton in Rodez.
On a windy day in the south of France, Froome and his teammates showed their superiority by riding at the front when the peloton stretched out and managed to put 24 seconds into their leader’s closest rival.
Froome’s main asset in the final stretch will be the strength of his teammates. Expect them to ride at the front in the mountains and to set a punishingly fast tempo — all designed to prevent others from attacking. If Froome is in form, he will be untouchable.
The collective strength of the Sky Team was on display Sunday when Froome was forced to change his rear wheel in the final 40 kilometers and got dropped.
‘‘I was just standing there on the side of the road with my teammate Michal Kwiatkowski, trying to change wheels. I thought it was potentially game over for me,’’ Froome said.
But Kwiatkowski quickly handed over his wheel and Froome was helped back to the front by teammates Sergio Henao, Vasil Kiryienka, and Mikel Nieve, erasing a 45-second gap.
Mikel Landa, who looks strong enough to be a leader in another team, was riding at the front but waited for Froome to catch up and the pair worked together to finish with the main contenders.
Froome’s rivals have now to find a way to unsettle and isolate him in the Alps before Saturday’s time trial in Marseille, where the British rider will have the upper hand in the race against the clock.