Manager Graham Westley says he detected a little complacency in the Stevenage ranks prior to their 2-0 home defeat to Notts County.
Boro beat Sheffield Wednesday 5-1 at the Lamex Stadium in midweek, but succumbed to goals from Lee Hughes and Ben Burgess against the Magpies.
"It's been a disappointment. We've been brought right back down to earth with a big bump," said Westley. "There was euphoria around the place following the big win we enjoyed against Sheffield Wednesday, and maybe some of the lads went into the game a little too over-confident.
"We created a few decent chances early in the game, but the finishing touch wasn't evident nearly enough and by the end of the game we've been punished in the harshest possible way.
"After the Sheffield Wednesday result most of our fans would have expected us to win quite comfortably, but we knew that wouldn't be the case. We spoke long and hard in the lead-up to the game about the threats County would present to us, and they've all been borne out.
"We've been turned over by goals from a couple of wily strikers who have both proved time and again that experience really does count for a lot. Hughes and Burgess have been scoring those kind of goals for years now and once again they've demonstrated exactly how dangerous they both can be."