The reigning world champions leave Marseille for Paris on Monday, reporting no major injury problems following their 12-10 victory over Australia.
And that will be a huge relief for the head coach, who has seen England's World Cup campaign disrupted by injuries at various points to the likes of Jonny Wilkinson, Jason Robinson and Andy Farrell.
England must now put the Wallabies triumph behind them though, and prepare for another huge challenge as they bid to reach a second successive World Cup final against all odds.
Scrum-half Andy Gomarsall said: "We have to keep building and building.
"There is no point peaking now, but we are going the right way.
"Have we already played our final? Rubbish, we just have to keep building."
While most red rose supporters would have anticipated a showdown against New Zealand at Stade de France next Saturday night, England's biggest Six Nations rivals now loom large.
Both previous World Cup meetings - in 1991 and 2003 - went England's way, although France recorded back-to-back tournament warm-up victories over them during the summer.
Ashton said: "We can compete at the same level as France, there is no doubt in my mind about that.
"We should have beaten them at Twickenham in August - I know that, and the players know that.
"We will go into the game with every confidence we have a team to trouble the French."
England, despite losing their second pool game in record-breaking fashion to South Africa, remarkably remain on course for a successful World Cup defence.
And Ashton added: "The South Africa game was a disappointing night for us all, but we knew we had it in us to put in better performances than that.
"The key thing was to knuckle down and start working to make sure that happened.
"Samoa and Tonga were effectively knockout games in our pool, and that bred confidence throughout the camp. There was a big performance waiting to happen.
"We will approach the France game with the same sense of excitement and anticipation that we approached the game against Australia.
"The anticipation going into this game (Australia) was something I have rarely experienced, and it was no surprise to me they came out and played the way they did.
"Yes, we can get better, but next weekend is going to be an even bigger challenge than beating Australia, there is no doubt about it in my mind."
England will head to Paris by train, where a rejuvenated French side await them just a month after they lost the tournament's opening game to Argentina.
"Everybody knew if one team could do it to New Zealand in this World Cup it would be France," said Rugby Football Union elite rugby director Rob Andrew.
"Even at half-time, although New Zealand looked in complete control, you just knew France were never going to be done in a massive World Cup game.
"Now it is about both sides refocusing everything they have got on the next big game.
"I have said all along you don't win the World Cup in the first fortnight.
"So many times you've seen the sides who have played the best rugby at the start of the tournament go out in the semi-finals or final.
"You certainly don't need to panic in the first fortnight. Clearly you might lose it in the first fortnight, but you are not going to win it."