Nicky Wroe’s crisp half-volley won the game late on to breach the stubborn Chairboys, who had Steven Craig sent off inside the opening 20 minutes.
It was the moment of magic Wilder bemoaned the U’s were lacking in their goalless draw at home to Portsmouth a week earlier.
Coming after an encouraging 2-2 draw at Championship side Charlton Athletic in the FA Cup last Tuesday, the United boss felt the Wycombe victory was another step towards recapturing their pre-Christmas form.
He said: “I thought all the players were getting back to where we were with the Dagenham and Morecambe games.
“We have had a blip over Christmas, but I saw signs against Portsmouth, where every part of the game apart from the final third was good.
“I definitely saw signs at Charlton and at Wycombe we stressed to the players it was important they played well, but that you get the right result. And they did that.”
The winning goal was a moment of real quality from Wroe, who is on loan from Preston North End until the end of the season.
With the exception of a short-term deal for Jonathan Henly to cover goalkeeping injuries, Wroe is the only signing United have made in January.
Wilder has not given up hope of making the additions he thinks are needed before the end of the month.
He said: “I’ll be trying to work on stuff in terms of getting players in.
“I still think we’re a bit light and I’ve expressed my opinions to the chairman.
“Hopefully we can sit down and address that.”
Dave Kitson missed the game with an ankle injury which emerged on the way home from Charlton.
He has had a scan, but at this stage it is not known how long the forward will be on the sidelines.
- Match highlights, via Oxford United's Youtube channel