The Chairboys seemed to have eased their way to automatic promotion until John Thompson's stoppage-time goal for the visitors left everything in the melting pot.
If Bury had managed to beat Accrington Stanley by two goals at Gigg Lane, the Shakers would have secured the final automatic place.
When the final whistle went at Adams Park it was still goalless in the north-west but the Wycombe fans who were listening to their radios were stunned when Alan Knill's side scored a late penalty.
However, Bury were unable to grab a second goal, as referee Andy D'Urso controversially appeared to blow the final whistle ahead of schedule following an impromptu pitch invasion.
That meant Peter Taylor's edged up into the higher division but it should all have been much more straightforward.
Wycombe started nervously and Notts missed two early chances through Sean Canham and Jamie Clapham to take the lead.
In the 20th minute, two blocks inside the six-yard box stopped Gavin Strachan and Matt Hamshaw from opening the scoring, so it came as little surprise when the visitors took the lead ten minutes later.
Thompson's long-range shot looked innocuous but it deceived keeper Jamie Young who could only help the ball on its way into the net.
Myles Weston went close to doubling Notts' lead before the break with a 25-yard effort that flew just wide but Wycombe responded well in the early stages of the second half.
Notts keeper Kevin Pilkington was forced to save Tommy Doherty's low shot before David McCracken steered Lewis Hunt's 52nd-minute cross home from close range.
Knowing that a draw would be enough, Wycombe sat back and they were made to pay for their negativity when Thompson curled a superb left-footed effort into the bottom corner of Young's net in stoppage time.
It didn't matter in the end and Wycombe can now start planning for life in League One and not have to worry about negotiating their way through the play-offs.