Wimbledon, of course, should have won with a swagger, by a Buckinghamshire mile. They looked more than one division better than Wycombe and led 2-0 with less than 20 minutes remaining.
Besides, Steve Brown's late equaliser - which took the game to a replay at Selhurst Park tomorrow - should not have stood. When the ball was played forward there appeared to be two, or possibly three, Wycombe attackers offside. On Saturday night the suspicion was confirmed by Match of the Day's Holy Trinity of Lineker, Brooking and Hansen.
But any neutral here on Saturday afternoon was tempted to rejoice with Brown, Wycombe's experienced midfielder, for he had a harrowing tale to tell.
He might not have played at all, having missed training on Thursday and Friday. On the first of those days, Maxwell, his son of only 15 months, underwent a serious stomach operation.
"It was a life-threatening, six-hour major operation," he explained, "and the last of a whole series of ops. But after what my girlfriend, Nichola, has been through I feel I can now put football in perspective. I just wish she could have been here today.
"I used to eat, drink and sleep the game. But not after what has happened to Maxwell. Now, if I have a bad game, I just make sure I do better next time. But I don't take a game home with me any more.
"I knew I was going to score today. When I get those feelings they are always proved right. I was going to wear a T-shirt saying so. I wish I did now."
Wycombe, for whom tomorrow's replay will represent their eighth match in the campaign, had never reached the fifth round before. And they appeared to have no chance of being involved in yesterday's quarter-final draw as they trailed Wimbledon by two goals in the 72nd minute.
Wimbledon, given confidence by their unexpected replay success over Middlesbrough in midweek, had taken the lead with a header by Mark Williams in the 32nd minute. Then Patrick Agyemang scored his first senior goal just before half-time.
Wycombe's PA announcer appeared to have given up the ghost at the interval, when he reminded everyone that the team had already created history by getting this far.
The catalyst for Wycombe's comeback came 10 minutes after the break when their manager, Lawrie Sanchez, whose winning goal for Wimbledon against Liverpool in the 1988 final had created one of the Cup's great upsets, brought on three substitutes.
The most influential of these was Sam Parkin. Just 19, and on loan from Chelsea, Parkin did not score but he has an eye for goal and immediately unsettled Wimbledon's back four.
His 72nd-minute cross led to Wycombe's first goal, by Michael Simpson, via the heel of Peter Hawkins and the right post. Then, following a free-kick on the edge of the six-yard box, conceded by Hawkins, Brown scored the equaliser, getting ahead of two Wimbledon defenders to scramble the ball over the line.
Sanchez said: "It's nice for the fans. This is not for Terry Burton and I. We have been here before. What I really want to do is get in a play-off position.
"Three subs can change a whole unit in the side. Sometimes the move can see you getting beat by six or seven.
"Martin O'Neill is God here. He set the benchmark. He got this club in the league and won trophies. If I can achieve half of what he achieved I'll be pleased. We can get into the First Division. We do not get big enough crowds for the Premiership. But we can survive in the First Division with crowds of 10,000.
Wycombe: Taylor, Rogers, Vinnicombe, Cousins, McCarthy, Carroll (Baird 55), Simpson, Lee (Parkin 54), Rammell (Bulman 55), Brown, Ryan. Subs Not Used: Westhead, Bates. Booked: Brown, McCarthy. Goals: Simpson 72, Brown 80.
Wimbledon: Davis, Cunningham, Holloway, Williams, Hawkins, Ainsworth, Ardley, Andersen, Karlsson, Euell, Agyemang (Gayle 67). Subs Not Used: Heald, Willmott, Gray, Hunt. Booked: Andersen, Holloway, Cunningham, Euell. Goals: Williams 32, Agyemang 44.
Referee: E Wolstenholme (Blackburn).
