In a match low on entertainment, it always looked as if a flash of brilliance or a mistake would settle the game, but instead O’Connor’s poacher’s instinct proved the difference as he poked the ball over the line from no more than a yard out after Nathan Bowden-Haase headed Paul Edgeworth’s last-minute corner toward goal.
This was a game which never really got going as both sides seemed content to play an aimless long ball game and give the ball away cheaply in the first half. One punt forward was dealt with poorly by Mangotsfield keeper Tony Court, and as the ball was headed back toward goal by O'Connor, defender Rob Scott got back to cover and spare his team-mate’s blushes.
Edgeworth put a free kick over the bar for Slough, before a loose pass from Hayes was almost punished as Jason Wood embarked on a long run, only for his weak shot to be easily dealt with by the returning Ricky Perks.
A brief spell of good football from the hosts brought about their best move, as Jack Allward strode forward and unleashed a dipping effort which bounced awkwardly and caused Perks to fist the ball away from his goal.
Skipper Edgeworth missed Slough’s first clear-cut opportunity late in the half, his powerful downward header from Buchanan’s deep cross bouncing down and over the bar.
Chris Herron replaced Hayes at the interval as Slough looked for greater creativity, but instead the long ball game continued. Bowden-Haase headed a quickly-taken long free kick from Edgeworth just over the bar as Slough were the first to threaten the goal.
Mangotsfield’s introduction of striker Daine O’Connor for the ineffective Luke Prosser looked as if it might pay dividends, and the hosts started to get the ball down and play football, but could not create a clear chance.
Instead, Slough’s best move of the game came as O’Connor worked an opening down the left and crossed for Simon Martin, whose header produced an instinctive save by Court, saving with his legs.
With twenty minutes remaining, the match had developed into a much more open affair, and Edgeworth should have given Slough the lead, but his fine jinking run resulted in Court parrying away a low shot.
Mangotsfield continued to play the better football, and Pilling shot just wide before Ricky Bush mistimed a headed effort from a corner.
With the prospect of extra time looming, Slough suddenly looked rejuvenated in the final ten minutes, and as the hosts invited the Rebels on, full-backs Fenton and Sweeney found opportunities to get forward and support the attack in Slough’s best spell of the game.
Simon Martin headed just wide after Ricky Perks’ huge long kick was allowed to bounce by the Mangotsfield defence, as keeper Tony Court looked shaky.
Elliot Buchanan then won the ball on the left and crossed into the middle, where an almighty scramble ensued. The ball was eventually cleared away after Craig O’Connor had an effort cleared off the line, and Mangotsfield counter-attacked with pace. Dean Pendry’s cross from the right was narrowly missed by the onrushing Daine O’Connor, desperately trying to get contact.
The game looked to be put beyond Slough as Dean Harper was caught in possession and Daine O’Connor found himself one-on-one with Perks, but the big Slough stopper spread himself well to block.
Just as it looked like the game would end goalless, Craig O’Connor’s late heroics sealed a short trip to Uxbridge in the next round for the Rebels.
Mangotsfield Utd Line up
Court, Allward, Smith, Pilling, Bennett, Scott (c), Wood (Pendry), Spill, Prosser (O'Connor), Knapman, Knighton (Bush). Subs not used: Britton, Trought.