The two sides remain locked together with Bristol Rovers on 47 points with just three games remaining, with the Cobblers remaining in the relegation zone on goal difference.
Northampton have been in the bottom two since September but temporarily edged out when Ricky Ravenhill's speculative effort from distance, combined with an error by home goalkeeper Matt Ingram who was later credited with the goal, saw them take the lead.
But on 18 minutes Wycombe were level. Aaron Pierre headed across goal into the corner of the net from Matt Bloomfield's free-kick after a foul by John Marquis.
"I thought we started the game really well but their goal punctured us," said Wilder.
"We gave them too many chances to put the ball into the box and their goal came from one of those, although it was a very good header.
"After that we allowed ourselves to get caught up in a bit of a game of basketball and we started to make some bad decisions.
"We got a bit better in the second half but Wycombe were always dangerous on the counter attack and we were perhaps a bit wary of that.
"There seemed to be long spells when we had the ball at their end but we needed to make better decisions and I don't think we were good enough in the final third to win.
"It was a magnificent effort by our supporters once again and they really drove us on."