Neither side could fashion a winner in a pulsating goalless encounter at The Walks - played in front of Lynn's biggest crowd of the season.
With 600 fans making the trip from Manchester, the game was played in a real cup-tie atmosphere.
FC United, who had skipper Dean Stott sent-off for two yellow cards, enjoyed the better of the first half before King's Lynn took the game to their big-name visitors in the second 45 minutes.
In a entertaining game of few chances, the Reds probably had the best one with Michael Norton forcing goalkeeper Alex Street into a fantastic reflex save with a header five minutes before half-time.
Lynn had chances to win the match too, most notably when centre-back Ryan Fryatt's header rattled the crossbar midway through the second-half.
Once again, it was a much- improved defensive effort from the Linnets to wipe away the memories of some poor performances at the back during September.
The match got off to a strange start when, just minutes in, the referee asked visiting defender Lee Neville and Lynn's Jordan Yong to change their cycling shorts because they didn't match the colour of their official shorts.
Both players were left stranded on the sidelines one after another as the referee twice waited for a break in play to allow them back onto the pitch - much to the frustration of both benches.
Greg Daniels headed over from a few yards out following a great cross from Matthew Wolfenden, before Street's wonder-save to deny Norton.
The Linnets were the better side after the interval with Ryan Fryatt crashing a header against the woodwork and Andrew Hall being foiled by Jon Worsnop.
Moments after striking the bar, Fryatt forced Worsnop into a double save as the United `keeper blocked a header and rushed back to tip the ball over the bar as it threatened to loop into the goal.
FC United midfielder Stott mistimed a challenge on Gary Mills on the touchline in front of the dugouts and the referee took the chance to use his red card by giving Stott his second yellow.
The Linnets knew that with the extra man advantage they had a superb opportunity to break the deadlock and take all three points, but FC United held firm.
|King's Lynn Town (4-5-1): Street,Thomson, Fryatt, Lee, Yong, Hall (Spriggs 80), Mills (C Clarke 85), Quigley, Jones, Jacob, Duffy (Bunting 46). Subs not used: Butt, Ward.
FC United (4-2-3-1): Worsnop, Brownhill, Daniels (Byrne 84), Stott, Davies, Neville, Wolfenden (Rodriguez, T1), Worsley, Norton, Wright, Mulholland (Walwyn 57). Subs not used: Greaves, Pearson.
Booked: Stott (x2), Worsley. Sent-off: Stott (74th min).
Referee: N. Smith. Attendance: 1,440.