The Blades missed the chance to move into the top six with a win over the relegation-threatened Tigers after Nouha Dicko’s second-half goal gave former United boss Nigel Adkins’ current team all three points.
Wilder was furious with his side’s performance at the KCOM Stadium, claiming they never got out of second gear, and was brutal when assessing United’s chances of securing a play-off, despite being just two points behind sixth-placed Bristol City.
“We got what we deserved out there,” he said. “Which was absolutely nothing. “I’ve been going on about trying to get into the top six but, looking at that, I must be off my head. I must be away with the fairies.
“Teams in the top six come here and find a way. Fulham, with all due respect, come here and win 3-0. Derby come here and do it, Cardiff come here and do it. As simple as.
“Listen, with all due respect we’ve not come up against an outstanding team, even with all their internationals, because their league position tells you that.
“I told them at half-time: ‘You’re going to get done 1-0 here unless you buck your ideas up.’ You could see it and I’m not Mystic Meg.”
Cardiff remain unhappy with Derby's decision to postpone Sunday's Sky Bet Championship game at Pride Park.
Dundee United boss Csaba Laszlo has been left hoping for St Mirren to slip up in the race to seal promotion to the Ladbrokes Premiership.
Crewe will consider starting Chris Dagnall when they host Forest Green on Tuesday.