Eddie Jones has been thrilled with the reaction from England's players over the last five weeks, but expects even more when they host Wales on March 12.
Jones has overseen three wins from as many matches since replacing Stuart Lancaster as head coach, the Australian guiding his new side to the top of the Six Nations table and raising hopes of a first grand slam for England since 2003.
Defending champions Ireland were brushed aside 21-10 at Twickenham last weekend, leaving only Wales and France in the way of a perfect campaign.
Jones, however, knows his players must find another gear if they are to finish the tournament unbeaten.
"The reason I took this job was because I believed the players were talented enough to be the best in the world and having coached them for five weeks now that only reinforces that view," he told the England Rugby website.
"We have a lot of hard work ahead of us, a lot of commitment, dedication to reach the goals. The talent is definitely there and the players have the attitude of wanting to improve.
"We know Wales is going to be a step up, so accordingly we need to step up in terms of attitude, commitment, preparation and selection. We are working very hard and we are right on track.
"We are focusing on improvement, if we get a one per cent improvement from every player over the next two weeks we'll be a much better team against Wales."