The loss to Brentford was only the Blades' second all season and Wilson was quick to point out that there are more than a handful of capable sides in the division.
"It annoys me when people dismiss League One as a waste of time, being full of pub teams," Wilson told the Sheffield Star.
"We take nothing for granted because we know there are some very good teams in this league.
"It hurts and one or two of them might have to open their eyes and smell the coffee a bit because we need to always play with the intensity that we did in the second half as that's what people will always have against us."
United still remain joint second, level on points with with Doncaster and MK Dons - three points behind leaders Tranmere.