Underhill passed into history, but Barnet may have a future in the Football League. If there have been more dramatic moments in the 106 years' football played on this sloping, idiosyncratic ground, they remain shrouded in the mists of time.
A 92nd-minute penalty save by Graham Stack protected an 81st-minute goal by Jake Hyde to leave Barnet in control of their own destiny. Survival on the last day, for the third successive season, beckons at Northampton on Saturday.
Inevitably, despite entreaties to stay off the pitch, the fans flooded on with the intent of a conquering army. It was a cross between the relief of Mafeking and the first day of the sales. Grown men screamed incoherently as they pawed at Stack, a journeyman who had flung himself to his right to beat away Joel Grant's penalty.
For some bizarre reason men in suits, at the back of the main stand, began to sing a Cab Calloway song. Their follow-up, a straight steal of Millwall's "No One Likes Us" anthem, was wildly inappropriate and out of keeping with the type of day that renews the romantic in us all.
Amid the bedlam, their head coach, Edgar Davids, removed his trademark glasses and waved them in a delirious mime. He had played heroically, until his 40-year-old hamstrings tightened five minutes from time. It still beggared belief to see one of the game's true artists, who has played for both Milan clubs, Juventus, Barcelona, Ajax and Tottenham, eking out the final days of his career in League Two, but this is no sinecure.
It wasn't the right moment to dwell on whether Barnet would ever again play in these parts. The local council regard them as a blight and the residents, who remained stoically behind net curtains in houses which backed on to the away end, will welcome the respite from traffic gridlock.
Football grounds are spiritual places, even when they are in a suburban maze, like Underhill. They are repositories of reminiscence, which can make one feel very old, very quickly. One of my favourite memories was forged here on 17 August 1991, when Barnet were beaten 7-4 in a suitably surreal debut in the Football League.
When it was over, the irrepressible Barry Fry sat in the home dugout. He was midway through a profane eulogy of Stan Flashman, the ticket tout who was his chairman, when the man himself appeared, dripping blood. Bizarrely, a window had fallen out of the police box and hit him on the back.
The Hive, the new complex which will house the club for at least the next decade, is just under six miles away, but, given the tribalism of football fans, it may as well be on the dark side of the Moon. The diehards hawked "Back2Barnet" T-shirts, but the sell-out crowd, which was swelled by football anoraks, contained too many strangers.
Wycombe fans were in party mood and welcomed their team with blue flares. The true believers, quaintly known as "Barnet Bovva", were chirpily defiant in the face of all-too familiar odds. The sun was out. The game kicked off 20 minutes late, largely because fair-weather fans were sinking pints on the balcony of the adjoining cricket pavilion.
Appearances could not have been more deceptive. This was the sort of occasion on which careers hinge. This was subsistence football, played under maximum duress. Barnet's size and catchment area suggest they will struggle to re-emerge from the scrum of former Football League clubs if they slip back into the relegation places at the death, yesterday's result having lifted them out with one game to go.
League Two remains an attritional environment and Wycombe have achieved miracles in straightened circumstances. They sell dreams, which just happens to be the name of their shirt sponsor. Several of yesterday's side are paid between £150 and £200 a week.
Barnet used the slope from the kick-off and not only for old time's sake. Wycombe defenders struggled to acclimatise to the ball's exaggerated bounce on a hard, bobbly surface and failed to deal with the movement of Hyde.
The public address announcer certainly captured the mood of quiet desperation, playing such anthems of hope as "Don't Stop Believing" and "Holding Out for a Hero". They did and, once Hyde had converted a low cross from the substitute Luke Gambin, they discovered a couple of heroes in Davids and Stack.
The sight of the Dutchman scuffling against players of half his age and a fraction of his natural talent was surreal, but uplifting. He was everywhere, managing the referee, Chris Sarginson, and even filling in at right-back when required.
As for Stack, he had one shot to save and he saved it. He had made his debut at Underhill for Arsenal as an 18-year-old and fought to reach his wife and parents after the final whistle. "An emotional day and a fantastic day," he said. "I go a long way back, with this place."
Once the pitch had been cleared, he took his three children on a lap of honour during which he handed goalkeeping gloves to anyone in the crowd who caught his eye. As the announcer proclaimed: "It's been a long, strange trip."
Barnet (4-1-4-1): Stack; Yiadom, Flanagan, Stephens, Johnson; Weston; De Silva (Gambin, 61), Byrne, Davids (Oster, 85), Marsh-Brown (Crawford, 78); Hyde.
Wycombe (4-5-1): Ingram, Harriman,Doherty, Johnson, Dunne; Grant, Lewis, Scowen, Spring, Wood (Andrade, 76); Kuffour (Morais, 76).
Referee Chris Sarginson.