The visitors took the lead in the 9th minute through James Foley after a ball is knocked down in the box and swept home from close range.
It's 1-1 just past the half-hour mark when Jack Bannister tried his luck from 20 yards and the ball flew past Albion 'keeper Greg Hall.
But on 38 minutes, FC United were reduced to ten-men when Kurt Willoughby was adjudged to have elbowed Billy Smart.
The visitors went 2-1 up after 63 minutes when Rob Hopley poked home after a goalmouth scramble.
The on 85 minutes, the home side were reduced to nine-men when Harry Winter was shown a second yellow card.
And in stoppage time, FC United ended the game with only eight on the pitch as sub Elliot Simoes was shown a red card, seemingly for two yellows after kicking the ball away.
Witton's league rivals Marine AFC ousted FC United's National League North colleagues Brackley Town – also on their own St James's Park patch.
The Mariners thoroughly shocked their hosts with a three-goal first half burst.
Finlay Sinclair-Smith opened the scoring in just the 7th minute and then James Murray added a second in the 32nd minute, with Sinclair-Smith bagging his second 6 minutes before half-time.
Whatever was said in the home dressing room soon worked as Brackley pulled two back in the opening 8 minutes of the second period through Adam Walker and then Matt Lowe.
But a battling performance from the Mariners saw them hold firm to record a terrific win.
There was an upset of sorts as Evo-Stik Northern Premier League Premier Division leaders Warrington Town beat National League North side AFC Telford United 2-1.
The Bucks did not get going at Cantilever Park until the final few minutes and then it was too little too late.
Bohan Dixon and Ben Garrity struck for the Northern Premier leaders. Daniel Udoh scored in second half stoppage time for the Bucks but the Yellows were well worth their win
Northern Premier League Division One East side Cleethorpes Town fought back from 2-0 down at home to National League North visitors Guiseley AFC to earn a second go.
It didn't look good for the Owls as, after a goalless opening 45 minutes, the Lions broke the deadlock through Will Hatfield after 62 minutes and then Kingsley James doubled their lead only 5 minutes later.
But Danny North scrambled the ball home to pull one back in the 84th minute and on 88 minutes, Scott Vernon headed in a dramatic equaliser.
Northern Premier League Division One West side Kidsgrove Athletic earned a home replay after holding NPL Premier Division Workington AFC to a 0-0 draw at Borough Park.
Famed cup side Blyth Spartans came from behind to book their place in the next round.
The National League North side won 2-1 at former league rivals Gainsborough Trinity, who are now plying their trade in the NPL Premier Division.
A 38th minute Sean Reid goal was followed by Robbie Dale’s 44th minute penalty on the brink of half-time turned the game on its head after an early goal from Trinity’s Shane Clarke gave the hosts the lead on 9 minutes.
National League North side Alfreton Town came through a tricky test at the Don Amott Arena against NPL Premier Division Mickleover Sports, whose Isai Marselia's 82nd minute reply came after Jordan Sinnott after 34 minutes and Richard Peniket had given the Reds a 2-0 interval lead.
Brett Solkhon scored a hat-trick of penalties as Southern League Premier Division Central side Kettering Town booked their place in the Fourth Qualifying Round with a 4-0 victory over NPL Premier Division Hednesford Town at Latimer Park.
Report courtesy of Steve Whitney from Non League Today