Substitute Danny Rose scored the game's decisive goal to end City's 364-day home unbeaten run as the Stags ran out 1-0 victors at Sincil Bank.
The Imps made two changes to Tuesday night's win at Forest Green Rovers, with former Mansfield men Matt Green and Matt Rhead replacing Ollie Palmer and Nathan Arnold.
Once captain Alex Woodyard had done the pre-match routine with referee Rob Jone, Green kicked the game off with City attacking the Bridge McFarland Stand in front of a packed-out Sincil Bank.
Danny Cowley's men started brightly with Harry Anderson and Green causing early issues. And it was Green who created the game's first real opening as he beat the high defensive line, rounded a rushing Conrad Logan by the touchline, squared for Knott but his effort was heroically blocked by the Mansfield man.
Green and Anderson continued to cause problems down the right channel as the latter set Michael Bostwick in the 18th minute, but his long-range effort rose comfortably above Logan's crossbar.
Lee Angol was brought down 25 yards from goal on the half hour mark, but MacDonald's low free-kick went wide of Paul Farman's post.
The downpour at became evident shortly after as Sam Habergham's throw slipped out his hands and went immediately out for a visiting throw just yards ahead, but City dealt with the following attack as Neal Eardley cleared upfield.
With 34 minutes gone, Dickie started a City attack down the right as he drove forward after dispossessing Angol, set Green, whose cross was knocked down by Rhead for Billy Knott, but his effort was superbly blocked again for another corner. The resulting corner was headed on goal by Sean Raggett, but Logan was equal to it.
The Stags' Hayden White brought Anderson down in the 43rd minute to give Knott the opportunity to deliver from the wide left. Steve Evans' side couldn't clear properly as Eardley's left-footed ball in found Raggett again, but Logan was equal to it once more.
City continued to press as Knott and Woodyard allowed Bostwick to get a shot off from the edge of the box, but once again it was deflected behind for a corner.
HALF TIME: IMPS 0-0 MANSFIELD TOWN
After a relatively quiet start to the second half, Danny Rose was brought on for Kane Hemmings for the visitors, and immediately won the visitors a free-kick as he was uphended by Bostwick 30 yards from goal. The resulting free-kick landed to Potter whose volley went into the car park behind the Bridge McFarland stand.
Josh Ginnelly was brought on for Matt Rhead on the hour mark as Knott reverted into a central role,
Mansfield took the lead in the 61st minute, as White's cross by the byline on the right looped over the City defence and subsitute White nodded home from yards out.
Ginnelly began to spring City into life as he forced Logan into a good low save after dancing through the Mansfield defence previously.
Anderson called Logan into action shortly after as he worked his way past two Mansfield men on the right before getting a shot off at the near post.
The Imps then made a double-sub as former Stag Ollie Palmer and Sean Long replaced Harry Anderson and Neal Eardley respectively. Bostwick soon saw the game's first yellow card for a late challenge on Calum Butcher.
Long and Palmer then combined as the former drilled an inviting ball across goal, with Knott inches away from connecting, but Mansfield scrambled it away.
Knott forced Logan into a fine save from the resulting throw-in in the 82nd minute as the ball landed for the midfielder in the area, but his half-volley was palmed away by the visiting goalkeeper.
Rose continued to show class as he drove forward and hit a dipping 30-yard effort just over Farman's bar.
FULL TIME: IMPS 0-1 MANSFIELD TOWN
1 Paul FARMAN
3 Sam HABERGHAM
9 Matt RHEAD
10 Matt GREEN
11 Billy KNOTT
15 Rob DICKIE
16 Michael BOSTWICK
23 Neal EARDLEY
25 Sean RAGGETT
26 Harry ANDERSON
30 Alex WOODYARD
2 Sean LONG (78 for HABERGHAM)
4 Elliott WHITEHOUSE
5 Luke WATERFALL
7 Josh GINNELLY (60 for RHEAD)
8 Ollie PALMER (78 for ANDERSON)
14 Jordan MAGUIRE-DREW
21 Josh VICKERS
BOOKINGS: BOSTWICK (79)
1 Conrad LOGAN
4 Paul DIGBY
5 Krystian PEARCE
7 Alex MACDONALD
9 Lee ANGOL
16 Hayden WHITE
17 Alfie POTTER
18 David MIRFIN
19 Johnny HUNT
23 Kane HEMMINGS
24 Calum BUTCHER
6 Zander DIAMOND
8 Jacob MELLIS
10 Paul ANDERSON (85 for MACDONALD)
11 Will ATKINSON (90 for ANGOL)
21 Omari STERLING-JAMES
32 Danny ROSE (59 for HEMMINGS)
12 Bobby OLEJNIK
GOAL: White (61)
REFEREE: Rob Jones
ASSISTANTS: Ken Haycock & Paul Thompson
FOURTH OFFICIAL: James Wilson
ATTENDANCE: 9.563 (1459 Mansfield supporters)