England head coach Simon Middleton insists there is "room for growth" in his side as they prepare to face Canada after twice thrashing New Zealand.
The Red Roses' successive record wins against the world champions laid down a marker before next year's World Cup.
England play world number three side Canada on Sunday and Middleton expects "a tougher game" at Twickenham Stoop.
Despite his side's 16-game winning streak, Middleton says they are "not the finished article".
The two victories against World Cup hosts New Zealand were the ultimate show of dominance from the world number ones.
Not only have England now won 16 matches in a row, only France have come within 25 points of the Red Roses during this run.
A late Sarah Hunter try was needed to edge a 19-17 victory against Canada last time they met in 2019, but with the way England are currently performing few would expect such a close scoreline on Sunday.
Although Canada have a strong Exeter Chiefs-based front row, they are without star forward Sophie de Goede who has opted to remain with her university side.
Middleton still believes Canada "will be a real challenge", especially up front.
"They pressure you and from that point of view it could be a way tougher game than the last two simply because of the physicality they will bring," he said.
'There is definitely room for growth'
Middleton will use the challenge to explore areas for growth in his side with less than a year to go until the World Cup.
He has handed flanker Sadia Kabeya and wing Heather Cowell debuts, while full-back Sarah McKenna gets the chance to start in place of Ellie Kildunne.
Lagi Tuima will audition for the 13 shirt in the continued absence of the injured Emily Scarratt after Holly Aitchison impressed there on the opening two weekends.
Competition for World Cup places will be fierce, with Scarratt expected to return before then and prop Bryony Cleall, back row players Sarah Beckett and Vicky Fleetwood as well as centre Amber Reed all currently on England's injured list too.
Middleton has some tough decisions ahead, but he is determined to make life harder for himself by seeing just how much evolution can be achieved before the tournament in New Zealand.
"Ultimately we'll get judged next year," he said.
"There is definitely room for growth. We have to maintain where we are in the forwards and go above that in the backs.
"We have everything in place to do that - the players, the coaches and the fixtures.
"This team is the fittest and strongest we've ever had by some way. That can overcome a lot of skill deficiencies or inexperience.
"We are a very good side but we are not the finished article by any stretch of the imagination."