Les Bleus lost 19-14 to Tonga last weekend and there has been talk of a mutiny within the camp ahead of Saturday's World Cup quarter-final.
However, Yachvili was adamant head coach Marc Lievremont has the full support of the squad with the collective goal of advancing to the World Cup semi-final at the expense of the team which eliminated them from the 2003 and 2007 tournaments.
Yachvili said: "We changed a lot; we talked a lot together this week.
"We didn't train for three months to stop at the quarter-final.
"It's the quarter-final of the World Cup and maybe we will never play again in the quarter-final of the World Cup. That's the motivation.
"We know that if we play the same way we played last week we cannot win against England.
"It's going to be very hard, but on Saturday it will be another team than last Saturday."
France have concentrated on ironing out their flaws since the Wellington defeat to Tonga which saw them advance to the last eight in unconvincing fashion.
Biarritz scrum-half Yachvili added: "During the quarter-final, semi-final and final, the most important thing is the basics and the English are the best, maybe in the world, at the basics.
"That's why we trained a lot on the basics this week.
"We have to put a lot of pressure (on them) and, as usual, be better in the forwards than them."
Yachvili highlighted England fly-half Jonny Wilkinson and centre Manu Tuilagi - particularly his ability to cross the gain line - as key dangers while recognising the challenge presented to break through their defence.
He added: "We respect a lot this team because they've conceded just one try since the beginning of the World Cup."
Avenging the losses in the last two World Cups is not on the agenda, according to Yachvili.
He said: "There is no revenge. We just know that the English are better in the World Cup.
"We will expect a lot from this team. This is one of the best teams in the world.
"We train this week to be as good as them.
"If we are efficient and if our forwards can be better than theirs, I think we can win against England."
France: M Medard, V Clerc, A Rougerie, M Mermoz, A Palisson, M Parra, D Yachvili; JB Poux, W Servat, N Mas, P Pape, L Nallet, T Dusautoir (capt), J Bonnaire, I Harinordoquy.
Replacements: D Szarzewski, F Barcella, J Pierre, L Picamoles, F Trinh-Duc, D Marty, C Heymans.
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