It had looked like Anthony Stewart had secured the points for the visitors. Defender Stewart got on the end of Josh Scowen's corner in the 72nd minute and his close-range shot went in off the inside of the post.
But Peter Murphy scored his second last-minute goal in a week to secure a point for the Reds and extend their unbeaten run to five games.
It is the third time this season Wycombe have been denied points with a late goal but Ainsworth was not too despondent.
"It happens and while it is two points dropped, I was encouraged by the performance of the team," said Ainsworth after the 1-1 draw.
"We should have put this game to bed and been three or four up and we should be closing games out at the end.
"But we are a young side and we need experience. We are learning and, if we keep performing like we did and stick the ball in the net, we will win more than we will lose."
- Sports & Recreation
- Josh Scowen