Alex got off to a dream start thanks to Anthony Grant's terrific strike in only the fourth minute and went on to boss the opening half-hour of the match.
They created several openings during this time but were made to regret not taking them as Wycombe grew in confidence after equalising through Paris Cowan-Hall.
Ainsworth said: "In the end, we're content to get the replay because that means we're still in the competition.
"I thought we played really well and you could see at the end that both teams were really going for it because I don't think the replay was desired by either manager.
"But I'm full of confidence going up to Crewe now and the key thing is we're still in the hat.
"We've got a lot of games coming up now and there were a few tired legs out there but I'm really encouraged by the way we played.
"I thought the way we knocked it about today in the second half especially was special and with a little bit of luck we could have had two or three more goals."