Not only did Cheltenham claw themselves back into the game but Wycombe midfielder Kevin Betsy – the game's outstanding player to that point – was sent off for foul and abusive language to an assistant referee when disputing a throw-in decision.
That piece of ill discipline resulted in high-flying Wanderers, who had produced some confident and controlled football in the first half, suddenly losing their way and play-off chasing Cheltenham sensed three points.
The Robins duly claimed all the spoils deep into injury time when Steven Gillespie's deflected shot from the edge of the box sailed beyond goalkeeper Frank Talia and into the net.
No-one could have predicted that outcome given the way that Wycombe dominated the first half.
Wycombe tore into their hosts from the kick-off with quick-fire passing and fluid movement across the pitch. Wanderers would have been disappointed to go into the break only 1-0 up.
The goal arrived after 16 minutes when Kevin Betsy crossed from the right and defender Roger Johnson, who had stayed forward from a corner, got up to head past goalkeeper Shane Higgs.
Prior to that, the Cheltenham defence had been forced to defend for all they were worth with Jermaine Easter shooting over, Matthew Bloomfield having a shot blocked after a good build-up and Tommy Mooney seeing a header cleared off the line by Jerry Gill.
Cheltenham created only two chances in the first half although one of them, a brilliant 25-yard free-kick from Grant McCann, struck the inside of goalkeeper Frank Talia's left-hand post and bounced out again.
Cheltenham slowly grew in confidence as the second half progressed with Gillespie a threat and substitute JJ Melligan providing fresh impetus.
The Irishman created the equalising goal with a free-kick that defender Michael Townsend headed down for Gavin Caines to smash into the net.
And Melligan was heavily involved during the closing stages as Cheltenham threw everything at the ten men before finally carving out the decisive breakthrough.