Manager Dario Gradi has insisted that he will not get carried away by Crewe's impressive pre-season form.
The Alex defeated Championship outfit Derby 2-1 at Gresty Road on Tuesday, having already beaten Premier League side Wolves earlier in the summer.
"It's difficult to assess when you're playing teams at a different level to yourself," Gradi told BBC Radio Stoke.
"You wouldn't have thought there were two divisions between us, but we won't get fooled by the win."
The 70-year-old Crewe boss continued: "That's what we've got to be careful of.
"We got two terrific goals tonight, so we've just got to make sure we don't fooled by the fact that we're winning."
Byron Moore and Danny Shelley scored for the Alex, who conceded early in the game from a set-piece.
"We've got a bit of work to do still on the defending," added Gradi. "We give corners away that we shouldn't and you really do worry about those situations.
"I'm going to have to practise it a lot more than I've done in the past."
Former Hibernian defender Chris Hogg played around an hour of the game after joining the club on trial.