Eddie Jones believes his England team have still not showed their best form after they brushed Australia aside in the World Cup quarter-final in Oita.
England are in the semi-finals for the first time since 2007 following a record 40-16 win against the Wallabies – who knocked them out four years ago.
There were two tries for Jonny May, over whom Jones allayed injury concerns, as well as scores for Kyle Sinckler and Anthony Watson.
Jones described Sinckler, who had a terrific game, as running like a “rampaging rhino”.
England will play New Zealand in the semi-finals after the All Blacks demolished Ireland, and Jones was in optimistic mood.
“We just want to keep challenging ourselves,” he said.
“We haven’t played our best yet and the challenge for us is how do we get better next week, how do we get better individually as a player, how do we get better as a team, and these World Cups that’s what it’s all about.
"You go from a quarter-final to a semi-final, and the semi-finals are always probably the toughest game of the tournament because you’ve got two teams desperate to make the final.
“Everyone empties the tank, and you’ve got to find a way in the week’s preparation to get a little bit better. So our challenge this week as a playing squad and coaching squad is how do we find ways to get better.
"We’ve already decided we’ll have a bit of a rest early in the week and then start training a little bit later.”
Jones had called on his players to invoke the “samurai spirit” before this game, and was delighted with his players’ response.
“It’s a do-or-die game today,” he said. “Everyone understands that and the best samurais were always the guys who had a plan but who could adapt, who had a calm head and they were full of aggression.
"I thought we were pretty much like that today, but the challenge is how do we get better because there’s always a samurai around the corner, so we’ve got to continue to get better.”
