Oldland took the lead on nine minutes when striker Simon Lashley hit his fifth goal in seven games but Ashton replied immediately to level the score.
Ashton, lying in third place in Division One after a great start to the campaign, then took the lead early in the second half before an inspired double substitution from manager Dale Dempsey turned the game. Throwing on Josh Williams and Tom Hutton, Josh equalised on 73 minutes with his fourth goal in six matches to take the tie into extra time.
Oldland were awarded a penalty four minutes into the second period of extra time for a foul and Hutton slotted home coolly to make the score 3-2. Both sides could have scored again but Oldland now progress into the first round where they will entertain Bishop Sutton from the Toolstation Premier Division.