The result was the U's worst home defeat for 13 years but their supporters had reason to be cheerful again after Michael Raynes headed in a 95th-minute winner to move the club within five points of the play-offs.
"Hopefully we've gone a little way in the last two results, winning 3-1 at Torquay and then this, in redeeming ourselves after last Tuesday," Wilder said.
"I think we're third in the form table and Barnet were sixth, so we knew we were in for a tough game.
"We missed some chances and then we started to drift a bit after that. We should have been out of sight at half-time.
"It was a massive week for us and we've done well so far. I don't think anybody was that bothered how we got the win, just so long as we did."
The lengthy period of stoppage time came after a shot by Barnet's Mauro Vilhete during the second half broke the side-netting, leaving groundstaff to repair the goal.
"We didn't deliberately do that with the net," Wilder joked. "But credit to the players, they kept going to the very end."