Updated

Tour de France leader Chris Froome and his Sky team are looking to Wednesday's time trial in a bid to extend his lead over key rivals who put a dent their overall victory plans.

Froome came under threat on a dramatic ninth stage on Sunday as Alejandro Valverde and Alberto Contador combined forces in a bid to weaken Sky's grip.

It left Valverde, who began the 100th edition hoping more for a top five finish than a place on the podium, second overall 1min 25sec behind Froome and, more importantly, unexpectedly revealed chinks in Sky's formidable armour.

Richie Porte, a key helper for Froome in the mountains, was a significant victim of Sunday's drama and is now virtually out of contention for a place on the podium.

Porte is hoping Froome can help restore his supremacy, and thus give Sky the upper hand, taking more time off his rivals in Wednesday's 33km race against the clock from Avranches to Mont Saint Michel.

"My hope is that it (race) will become a little bit more controlled, and it is going to get easier after the time trial," said the Tasmanian.

Valverde is not considered a strong time triallist but nevertheless is hoping for more of the same kind of racing when the field heads into the Alps next weekend.

"The race is far from over and will take a significant turn once we go into the Alps for four tough stages," the Movistar team leader said on Monday's rest day.

"But we saw yesterday that Sky are not as strong as they were last year and if Froome is just like yesterday in any of them (stages), we can do damage."

Sky's collapse on stage nine was still the main talking point on Monday, but team principal Dave Brailsford was quick to give Froome a deserved pat on the back.

"To use a boxing analogy, he's taken the biggest right hook on the chin and he didn't flinch," said Brailsford.

But Brailsford, the man who helped mastermind British track cycling's successful quest for Olympic glory in Beijing and London before transferring his talents to road racing, admitted a change of strategy may now be needed.

"We've learned some lessons and there are some valuable lessons to be learned that we will take into the rest of the race," he said.

"We will adapt our strategy for the rest of the race. I'm not going to go into the details of what we're going to change."

Contador, the two-time winner whose 2010 title was handed to Andy Schleck following a positive test for clenbuterol, had shown chinks in his armour when he lost nearly two minutes to Froome on Saturday.

Having kept pace on Sunday but failed to attack on the final climb to La Hourquette d'Ancizan, the Spaniard sits in sixth place 1:51 in arrears.

While Valverde highlighted the potential weaknesses in Sky, who scored a 1-2 finish in Paris last year with Bradley Wiggins, who is absent, and Froome, Contador was more hesitant.

"It is always good to see that his team has weaknesses but that will not become a habit," he said.

The Spaniard added, however: "What happened yesterday (Sunday) surprised more than a few people. If that happens again, we will need to take advantage."

With the exception of Wednesday, the coming week is unlikely to change much in the battle for control of the race but Contador, 30, hopes the final week will see the situation turn in his favour.

"Yesterday was not the day but I hope we will take advantage in the Alps."

He added: "Of course I am going to try something. We need to know when to take risks, especially when everyone is struggling."