Late controversy denied the U's a vital win on Saturday afternoon.
The U's looked set for a 1-0 win thanks to a cracking Ian Henderson goal, but the Wanderers grabbed a dramatic late equaliser.
And it infuriated the Colchester players, most of whom flocked to the linesman in angry protests that hands were involved in Gareth Ainsworth's effort.
Manager Aidy Boothroyd was equally incensed after the final whistle as the U's were pegged back by that controversial goal.
The U's were almost in within the first thirty seconds of the game as Henderson threaded a great ball through to Gillespie, but Hinshelwood got back in the nick of time to take it away from his toes.
Gillespie then escaped down the left wing and centred the ball into the six yard box, which was well defended in the middle.
Another clever ball to the pacey forward on three minutes almost got him away before the keeper blocked the ball away, and Platt couldn't keep his footing to get to the ball for a follow up effort.
The U's had started brightly, but the visitors went close on nine minutes as Ainsworth was left on his own at the back of the area and he glanced a header just beyond the far post as Williams was happy to watch it go by.
After that bright start, the U's then lost their way slightly, but Hinshelwood went into the book for a foul on Gillespie just inside the Wycombe half as the U's forward went to spin his man.
The visitors were using the width of the pitch, with Ainsworth and Kelly combining well down the right.
It was down the Colchester right that they went close midway through the half, as a low Ifil cross was stepped over by Lisbie and it was cleared just before Gillespie pounced.
Chances were at a premium for both sides and, in a congested Wycombe penalty area, Prutton twisted and turned before firing an effort over the crossbar with his left foot.
They followed that up with another move, this time at pace, as Henderson's cross was returned into the centre by Ifil, and Gillespie headed over at a stretch.
The striker came close with a corner on 40 minutes, heading an effort which was deflected over the bar from close range.
The front man then went into the book for a challenge on the keeper when the two went to get to a Platt through ball.
And Izzet joined him in the book as, after a misplaced pass, Izzet tracked his man down and ended up tripping him on their path to goal.
Harrold had a half sight of goal, but Williams collected his header comfortably and it summed up a half of half chances.
The U's had a chance after the restart, Platt knocked down to Gillespie and as he wriggled his way clear, he went to ground just as he shot and the shot was over the bar.
At the other end, a flowing Wycombe move saw the ball moved on three times across to Ainsworth, and Izzet's diagonal run behind the defence saw him into position to block.
The U's went on the attack again and the ball was worked into the path of Prutton on the edge of the box and his driven effort swerved wide.
And it was an open start to the half. Betsy was threaded through into the box and it took a strong challenge from Okuonghae to block him as he drove towards goal.
White then took the balls off the toes of Harrold as he went to shoot as both sides threatened to find the game's opener.
The visitors then had the best chance of the game on 56 minutes as Beavon stepped past two challenges and curled in a fine effort that Williams tipped over.
From the resulting corner, Hinshelwood flicked on at the near post and Ainsworth was flat footed as it flashed past him at the far upright.
And the Chairboys were to live to regret those misses as the U's got their noses in front with a great goal.
Izzet picked out Henderson with a superb cross field ball over his full back. The wide man cut inside and, as the ball dropped for him, he lashed in an effort beyond the keeper and into the net.
The U's were on the front foot and winning tackles and, from distance on 64 minutes, Gillespie stung the hands of Heaton, who held the ball well.
The home side were unable to capitalise on taking the advantage though, as a spell of possession followed for the Chairboys.
The visitors were to make the first change in the game, taking off Mousinho for Matt Bloomfield for the final quarter of the game.
The substitute could only watch on in despair as a great low ball was delivered from the right and team mate Beavon couldn't work his feet to finish the move with a goal.
The U's made their own substitution on 70 minutes, replacing goalscorer Henderson with Anthony Wordsworth.
And the home side started to retain possession a little better as the half wore on, but there was a sharp inhalation of breath around the ground as Ainsworth's darting run into the box almost saw him clipped by Prutton.
Both sides made another sub with fifteen minutes remaining - O'Toole coming on for Gillespie for the remaining period of the match.
And, after the introduction of Phillips, the visitors brought on Pittman for the last 10 minutes, the front man having scored the equaliser at Adams Park earlier in the season.
The visitors were getting sights of goal and a ball laid back to Keates 25 yards out seemed destined for the bottom corner before White intervened.
From the corner, there was a free header at the far post, but the effort was off target, much to the relief of the home support.
But the pressure was building on the home defence, and as the final five minutes arrived, Vincent was introduced to try and provide fresh legs further up the field.
And that pressure told as the visitors equalised deep into injury time. The ball was not cleared and it was met in the middle by Phillips to divert it past Williams.
The U's players were incensed and, in scenes reminiscent of the Ireland v France game, the U's players believed that they had seen a handball in the six yard box.
Despite lengthy protestations by half of the U's team to the linesman, the goal stood and two valuable points had slipped from their grasp.
Indeed, such was the U's anger that both Prutton and Williams were booked for comments they made to the referee as the match didn't end in a home victory.