The Italians have never beaten England since joining the Six Nations 10 years ago and are rank outsiders to break that duck when the pair lock horns in Rome this weekend.
But England’s last visit to the Stadio Flaminio ended in a tight 23-19 victory two years ago and Haskell, who scored two tries in last week’s opening victory over Wales at Twickenham, says they should not be taken lightly.
“There are enough experienced players here to know not to get carried away with a victory,” said the 24-year-old Stade Francais back-rower.
“I think you have got to take everything you can out of it, which we have done – confidence which has gelled us together even stronger than we were before.
“But that picture finished as of the final whistle on Saturday. You allow yourself to have an evening of reflection but come Sunday, Monday it is about Italy. They bring a massive challenge which we are going to have to be on the money to make sure we compete with.”
During their nine years in the competition, the Italians have won just six games and drawn another, but Haskell believes they are more than capable of adding to that tally this year.
“It is a surprise to me that they haven’t really scalped anyone properly because they have the potential ability to do that,” he went on.
“They are just waiting to put in a real performance that will ruin someone’s day. If we allow them to impose themselves, we can come up short.
“And we know that going into their own back yard, they are very, very passionate people and we are going to have to make sure that we work until we can’t work any more.”
The Italians are renowned as arguably the best scrummagers in the northern hemisphere, but England scrum coach Graham Rowntree believes rookie Leicester prop Dan Cole can rise to the challenge on his full debut.
“We understand that at his age  he is work in progress,” Rowntree said. “It doesn’t get much tougher for a first start but we wouldn’t put him in there if we didn’t have confidence in him to handle it. His temperament is his strength.”