Argyle found themselves 3-0 down at home and surely heading for another season in League Two before goals from substitutes Jason Banton and Zak Ansah in the final minutes kept them dreaming of a trip to Wembley.
They now head to Adams Park knowing a repeat of their 2-0 victory there in February would see them reach the League Two play-off final against Southend or Stevenage.
And Argyle manager Sheridan says his squad believe they can turn things around.
“The players are positive,” he told the Western Morning News. “They think we have got a bit of a lifeline, with the two goals we got at the end on Saturday.
“We looked down and out but we got the two goals and we are right back in it. We really are.
“Gareth (Ainsworth, Wycombe boss) was probably thinking they would be going back to Wycombe 3-0 up, and it would have been really difficult for us, but the tide has turned.
“I have watched the play-off games and some of them have been unbelievable. You just don’t know what’s going to happen, with lots of twists and turns.”
Ainsworth has called on the Wycombe supporters to play their part in what will be their biggest crowd of the campaign.
The Chairboys have only won two of their last four matches but the Blues manager is confident his fans can make the difference.
“The fans who follow us week in, week out have been phenomenal and so much of what we’ve achieved on the pitch is down to their support, getting behind us when we’ve got our backs against the wall and helping the lads believe that we can achieve success together,” he told the club’s official website.
“Now we need everyone to pull together to do the same on Thursday night, so whether it’s your first game or your 1000th game following us, give everything you’ve got, bring your mates and let’s do something amazing that future generations of Wycombe fans can remember us by.”