Although City had the better of the early exchanges with Tom Miller coming the closest to opening the scoring when he saw his downward header from a Nicky Nicolau free-kick superbly kept out by Tony McMillan, they found themselves a goal down in the 18th minute when Simon Grand was allowed to connect with an inswinging corner to nod home from close range.
Grand added a second seven minutes later when he got on the end of a header across the box after City failed to deal with a free-kick and shortly after the half-hour a weak Miller clearance ended up with Andy Owens spectacularly curling home a long-range effort over the stranded Paul Farman.
Jamie Taylor reduced the arrears before the break when he drilled home from just inside the box whilst after the interval the striker headed over McMillan only for his effort to be hacked off the line.
Andrew Boyce rattled the woodwork with a header but, shortly after Conal Platt made a welcome return from injury as a 76th minute substitute, Owens squared for Karl Ledsham to make it 4-1.
An excellent Vadaine Oliver header completed the scoring but City's first half lapses ultimately proved to be their undoing with the Sandgrounders' victory lifting them above the Imps in the Blue Square Bet Premier table.
With injuries ruling out Scott Garner and Jake Sheridan, there were two changes to the City starting line-up for this Blue Square Bet Premier game against Southport at Haig Avenue. Dan Gray dropped back to partner Andrew Boyce in the centre of defence with Alan Power starting in midfield whilst Conner Robinson was handed a start on the right and Vadaine Oliver returned up front. New loan signing Chris Bush was on the bench.
The home side kicked off in front of a sparse crowd but it was the Imps who were the first to press with a swift counter-attack after a Southport free-kick was headed clear ended with Robinson and Jamie Taylor exchange passes before the former was denied by home 'keeper Tony McMillan who was quickly off his line.
At the other end a Karl Ledsham effort was ruled out for offside after the Southport man strayed too far forward after a ball into the box bounced around inside the area. A foul by Tom Miller on Andy Owens then forced the Imps to defend a free-kick into the area.
City's response saw a long Dan Gray throw-in cause problems for the home defence and as the home side responded they won the first corner of the game which was dealt well with by Oliver at the back post.
Play switched to the other end again with Taylor firing wide, although he had both Robinson and Jake Thomson up in support. A cross from Oliver then hit the hand of his marker and when the free-kick was played into the mix Tom Miller was denied by a superb one-handed save by McMillan who scooped the City defender's downward header away at full stretch.
The home stopper's save was rewarded in the 18th minute when his side took the lead; the Sandgrounders forcing two corners in quick succession and when the second was curled into the six-yard box it was met by Simon Grand who flicked a header past Farman despite being surrounded by blue shirted markers.
A couple of minutes after the restart a sliding challenge from Thomson on Ledsham earned the recent acquisition a yellow card but things got worse in the 25th minute when Grand bagged his second of the game. Again the source was a set-piece; this time a Whalley free-kick was nodded across the area into Grand's path and he easily beat Farman with a close-ranger header.
A shell-shocked City looked for a quick response with Taylor testing McMillan with a curling 20-yard effort but it wasn't long before the home side were pressing again and when Miller failed to get any purchase on a header following a ball down the middle, Andy Owens was quick to latch on to it and duly curled home a superb first-time finish from 30 yards out
The goals continued five minutes later but this time the action was at the other end as, after Power released Nicolau down the left, his low centre was half-cleared by McMillan under pressure from Oliver and there was Taylor to rifle home from just inside the box to reduce the arrears.
City quickly won their first corner which was cleared whilst shortly afterwards a late challenge on Robinson saw Godfrey Poku see yellow with Miller heading Power's resultant free-kick a foot over.
Three added minutes elapsed without further incident so with the Imps 3-1 down strong words will no doubt be being uttered inside the visiting dressing room during the half-time interval.
HT Southport 3 Imps 1
Both sides emerged unchanged for the start of the second half with a succession of throw-ins for the home side ending in a corner on their left which was cleared by Oliver. Owens wide after long ball down the middle almost caught City out again.
City's response saw Oliver pressure the home defence into an error which ended up seeing Taylor head over McMillan only for a back-tracking defender to hack the ball off the line. This proved to be Taylor's last action as he was replaced by the fresh legs of Colin Larkin in the 54th minute.
A couple of minutes later Miller was booked for foul despite appearing to win the ball and when Whalley curled in the free-kick, the ball floated over Farman before bouncing to safety off the woodwork.
Miller was spoken to again by the referee after another challenge went against him and Mr Joyce was in the action shortly afterwards, booking Boyce for a late foul on Chris Lynch after the centre-back's frustration at not being awarded a penalty after he appeared to be tripped in the box got the better of him.
A minute later, and shortly after the hour mark, Power released Larkin but he was denied by a fine McMillan save. Before the corner was taken Gray was forced to receive treatment after taking a knock whilst Chris Bush replaced Paul Robson at left-back. When the corner was taken, Nicolau's delivery was met by the head of Boyce and although his effort beat McMillan the ball crashed against the bar.
With 20 minutes remaining Oliver came close to connecting with a Larkin cross before Nicolau tested McMillan with a chipped effort following some decent build-up play. Conal Platt then made his long-awaited comeback after almost a year out with a broken leg, replacing Nicolau on the left.
Despite enjoying the better of the second period, City found themselves three down again when a Southport attack down the right ended with Owens squaring for Ledsham to prod home.
City's heads didn't drop though and in fact Oliver's went up with the striker connecting with a deep Miller cross before planting a firm header past McMillan to make it 4-2.
A triple substitution for the home side saw Charlie Joyce, Steven Tames and Michael Bakare come on for Andy Owens, Chris Almond and Shaun Whalley. Bakare was quickly in the action, fouling Thomson before kicking the ball away for a yellow card.
With the clock quickly ticking down a quickly-taken Platt free-kick saw Power pick out Larkin only for the ball to run away from the substitute as he prepared to bear down on goal
The Fourth Official indicated that a minimum of five minutes were to be added on but the early period of this saw the ball spend most of the time out of play with numerous throw-ins for the home side giving them ample time to eat up the seconds.
FT: Southport 4 Imps 2
City: Paul Farman, Tom Miller, Andrew Boyce, Dan Gray, Paul Robson, Alan Power, Jake Thomson, Nicky Nicolau, Conner Robinson, Jamie Taylor, Vadaine Oliver.
subs: Chris Bush (for Robson 63), Conal Platt (for Nicolau 76), Bradley Barraclough, Colin Larkin (for Taylor 54), David Preece.
goals: Taylor (37), Oliver (80)
bookings: Thomson (20), Miller (56), Boyce (61)
Southport: Tony McMillan, James Smith, Chris Lever, Simon Grand, Andy Parry, Chris Lynch, Andy Owens, Godfrey Poku, Shaun Whalley, Karl Ledsham, Chris Almond.
subs: Zac Hibbert, Charlie Joyce (for Owens 82), Steven Tames (for Almond 82), Liam Willis, Michael Bakare (for Whalley 82).
goals: Grand (18, 25), Owens (32), Ledsham (77)
bookings: Poke (43), Bakare (84)
Referee: Ross Joyce
Assistants: Natalie Walker & Nicholas Barnard
Fourth Official: Dave Croft
Attendance: 815 (69 City supporters)