Ryan Allsop was Wanderers' man of the match in a pulsating 0-0 draw with local rivals Oxford United at Adams Park, producing a series of saves to deny the U's.
The visitors' attacking axis of Gavin Whyte, Ricky Holmes and Jon Obika caused a number of problems during the first half and the pick of Allsop's numerous saves was a stunning fingertip effort to turn Holmes' strike onto the crossbar.
Wanderers came on strong in the final 30 minutes and thought they'd snatched a late winner when Adebayo Akinfenwa headed home, but he was caught offside, ensuring the spoils were shared.
Gareth Ainsworth made two changes to the side that started in the narrow loss to Charlton, with Curtis Thompson and Adebayo Akinfenwa making way for Matt Bloomfield and Fred Onyedinma.
A frenetic start almost saw the U's open the scoring in the scrappiest manner inside two minutes, taking advantage of indecisive defending and kind ricochets to bundle their way goalwards, only for Joe Jacobson to save the day inside the six-yard box with a last-gasp challenge.
Wanderers survived, but then lost Anthony Stewart to injury, with Michael Harriman coming off the bench on six minutes and taking up the right-back slot as Jason McCarthy moved inside.
And they regrouped, weathering the early storm and could have taken the lead when Randell Williams crashed a header against the bar from Joe Jacobson's wicked inswinging corner.
In the battle to win the ball there was a clash of heads between two United defenders and Cameron Brannagan came off worse, requiring a prolonged period of medical attention before departing on a stretcher with the best wishes of everyone inside Adams Park. Josh Ruffels took his place.
Jon Obika headed a cross over the bar once action was underway again, before Matt Bloomfield threatened with a low cross which was well cleared.
Shandon Baptiste came close to an excellent opener when he deceived Harriman on the halfway line and surged all the way into the box, cushioning a shot narrowly past Ryan Allsop's far post.
The U's gathered momentum and Allsop needed to be alert to keep out Gavin Whyte's powerful shot and follow-up header from the rebound, before the keeper produced an unbelievable save to tip Ricky Holmes' effort onto the bar after the attacker picked up possession and unleashed a fine strike which looked destined for the top corner.
The keeper was called into action again when the lively Whyte created space for himself and shot too close to the Wanderers' number 1, before Wycombe looked to alleviate the pressure with a well-worked move which saw Mackail-Smith tee up Williams, whose shot was blocked.
There were 10 minutes of injury time due to the earlier delays, with Holmes seeing his curling free-kick tipped away by Allsop before mis-hitting a strike from 20 yards.
Holmes had another shot blocked at the end of a mazy run with Baptiste curling over with the loose ball, though a spectacular effort on the volley from Bryn Morris fizzed wide which would have been one of those 'against the run of play' moments.
The final save of an action-packed, 55-minute long half was comfortable for Jonathan Mitchell, who hung on to Joe Jacobson's swerving shot, before time was called, giving Wanderers a breather having done well to keep the scores level after being pushed onto the back foot for long spells.
Curtis Nelson headed wide from a corner at the start of the second half, before a combination of Sido Jombati, Mackail-Smith and Onyedinma almost forced a loose ball into the Oxford net from a free-kick before it was cleared over the bar to safety.
But normal order was resumed when John Mousinho this time tested Allsop, who tipped his powerful header over the bar, and then Baptiste drilled over from 30 yards.
Holmes' near-post shot was saved by Allsop after yet another venture into the Wycombe box, and Obika flicked a header over the bar from a cross, but Wanderers needed to make a change, and it was Adebayo Akinfenwa who sprang off the bench on the hour-mark to take Mackail-Smith's place.
Oxford made a change of their own, replacing James Henry with Marcus Browne, but the introduction of Akinfenwa had given the hosts a new lease of life, with Bloomfield threatening with a dart into the box before a long throw was flicked dangerously across the six-yard line before the keeper gathered.
Joe Jacobson was booked for a late tackle before Luke Garbutt hit a low free-kick straight into the arms of Allsop, and Sido Jombati followed him with a yellow card for a pull on Jon Obika.
It was Obika's final contribution, being replaced by Sam Smith, before Baptiste collected a yellow for tugging back Williams on a counter-attack. with Jason McCarthy and John Mousinho also booked for an altercation.
But by now it was well and truly a two-sided affair, both sides capable of going on to win. Onyedinma raced away down the left and fired into the side netting, before Paris Cowan-Hall came on for Randell Williams - the final sub of the game.
Then Dominic Gape was shown yellow for clipping the heels of Holmes, before Oxford keeper Mitchell spilled a high cross and was thankful to his defender for blocking Cowan-Hall's shot as it broke loose.
Wanderers thought they'd won it when Akinfenwa crashed home a header from Jacobson's free-kick, only to see their celebrations cut short by the linesman's flag, as the game entered six minutes of stoppage time.
It eas edge-of-your-seat stuff, but derby day was to end in a stalemate in one of the best 0-0 draws you'll see.
Attendance: 6,879 (1,816 away)
Blue £1 Ticket: 06941 (£715.50 prize)
Orange £2 Ticket: 26324 (£139 prize)