Ainsworth's men played for almost an hour with ten men against the League One side after experienced midfielder Matt Spring received a straight red card.
And after going in at half-time two goals down the Chairboys regrouped and bowed out with their heads held high.
He said: "I am a really proud man because losing Matt Spring was a huge blow, and it's so difficult when you go down to ten men.
"I said to the boys to try and nick the second half, and I thought they were outstanding. It's one of the best defensive performances we've had all season.
"Kortney Hause came in at 17-years-old for only his second game and was outstanding. We had so many people playing out of position in midfield who all dug in, and I think we had five or six players under the age of 20.
"A performance like that away from home against a side from the league above was superb, and I've got nothing but pride for the boys. Nobody should have their heads down after that.
"We can build off this and the spirit it has given us. I thought we probably had the better chances in the second half and we will go again on Saturday. I am quite upbeat."