Duncan Watmore rescued a point for Sunderland in the dying stages of a remarkable afternoon at Adams Park.
The Black Cats, who had been reduces to ten men as Tom Flanagan left the pitch with injury, had struggled all afternoon to test the Wycombe goalkeeper.
But just as they looked set to fall to their third defeat of the season, Ryan Allsop fumbled an effort from Grant Leadbitter and susbstitute Watmore fired it into the back of the net.
It was a jubilant end to a feisty afternoon in which Wycombe had frustrated Sunderland with a direct display and significant timewasting throughout the second half.
It summed up the occasion that it finished with an almighty scrap in the techincal area as both sides clashed.
That ended with George Honeyman and Nathan Tyson, both of whom had already been substituted, seeing red.
Remarkably, Marcus Bean was the next to go after picking up a second yellow for a challenge on Duncan Watmore, who was left in agony.
The Black Cats had come into the game riding the high of four consecutive wins and their place at Wembley booked for the end of the month.
Yet from the first minute they struggled with Wycombe's direct approach and were indebted to Grant Leadbitter as he made a big covering tackle just two minutes in, Wycombe midfielder Matt Bloomfield bursting into the box.
There was little tempo to the contest, disrupted early on by an injury to goalkeeper Ryan Allsop.
He was eventually able to continue and the home side continued to threaten, with Manchester City loanee Luke Bolton missing a glorious chance. Sunderland failed to deal with a long ball through the middle and Nathan Tyson was able to break free on the left, crossing low to the back post where Bolton somehow sliced his effort high and wide.
Jack Ross cut a frustrated figure as his side struggled to get any foothold on the game, Will Grigg badly isolated and the wingers offering little threat.
Aiden McGeady had the only shot of substance, but that was a poor effort that drifted wide.
After his horror miss Bolton picked up injury to compound his misery, with Paris Cowan-Hall brought on and contributing to the opening goal.
Sunderland lost the ball in a dreadful area and the home side had an opening, working the ball to the back post where Alex Samuel had an easy finish.
Samuel continued to be a threat, the lively forward causing problems problem for the Sunderland centre-backs who looked uncertain.
Ross will have been relieved to see his side get to the break without futher damage, and replaced Reece James with Adam Matthews.
James had missed the win over Bristol Rovers earlier in the week through injury.
Sunderland started the second half considerably better and came within inches of equalising, Tom Flanagan rising highest as a free kick was floated into the box, thumping his header onto the crossbar.
Wycombe responded by nearly forcing a set piece goal of their own, Cowan-Hall just unable to connect at the back post as a corner was flicked onwards.
The home side looked to have steadied and it took an oustanding piece of individual skill from Aiden McGeady to unsettle them.
He spun away from two markers on the touchline and when his cross dropped loose in the box, it took an excellent block to deny Lewis Morgan.
The Celtic loanee was replaced by Duncan Watmore, Sunderland improving marginally from the first half without forcing Allsop into any significant action.
McLaughlin had to be alert at the other to deny Bloomfield as he toom aim from inside the box.
Sunderland's frustrations were summed up when Jack Baldwin was booked from the substitutes bench, running on the field to try and move the ball down the pitch as Wycombe killed time.
Jimmy Dunne forced a save from Allsop as he headed a corner towards goal, but the home side were comfortable enough.
Sunderland were forced to finish the game with ten after Tom Flanagan took a nasty kick to the face, the home side seemingly comfortable until Watmore's intervention.
Stoppage time ended in acrimony after the extraordinary melee, with Bean's second yellow dragging the game on further still.
Sunderland ended with a point that at one stage looked unlikely, but with ground lost on Barnsley in second.
Sunderland XI: McLaughlin; O'Nien, Flanagan, Dunne, James (Matthews, 45); Leadbitter, Cattermole, Honeyman (Watmore, 60); Morgan (Gooch, 67), McGeady, Grigg
Subs: Ruiter, McGeouch, Baldwin, Power
Wycombe Wanderers XI: Allsop; McCarthy, Jacobson, Stewart, Jombati; Bean, Cape, Bloomfield (Thompson, 90), Bolton (Cowan-Hall, 28); Samuel, Tyson (Harriman, 83)
Subs: Akinfenwa, Owens, Kashket, Ma-Kalambay
Bookings: Samuel, 10 Cattermole, 47 Bean, 54 McGeady, 78 Baldwin, 80 Flanagan, 85
Red Card: Honeyman, 90 Tyson, 90 Bean, 90