Kayden Jackson lashed home a dramatic late winner deep into stoppage time as the Blues came from a goal down to beat AFC Wimbledon this evening.
It looked as though the reality of League One was going hit home for the hosts as they trailed after Nesta Guinness-Walker's goal silenced Portman Road before the break, but James Norwood superbly met Alan Judge's in-swinging corner to head home and level.
Ipswich tails were up from then as the noise inside Portman Road grew and grew, with the roof blowing off when Jackson collected a lobbed ball back into danger and lashed into the back of the net.
The three points will be welcomed but the performance for much of the contest was well below what Lambert will expect from his side and there is plenty to work on heading into Saturday's trip to Bolton.
The visitors were content to sit back and take their chances when they came for most of the game, with the Blues going up a gear in the second half following the introductions of Jackson, Alan Judge and debutant Anthony Georgiou.
The Blues had a new drive and attacking intent following Lambert's substitutions, making their quality county to secure all three points.
There was a surprise on the team-sheet when it was released at 6.45pm, with skipper Luke Chambers relegated to the bench for the first time in the league since the final day of the 2012/13 season.
James Wilson started in his place, while Andre Dozzell and Idris El Mizouni were given starts in place of Gwion Edwards and Kayden Jackson, as Paul Lambert switched to a 4-3-3 system.
The Town boss referred to his side's performance against Sunderland as 'rock and roll football' following the 1-1 draw last time out at Portman Road, but the opening exchanges of this contest was anything but.
Neither side were able to string any noteworthy passages of play together during the opening half an hour, before Danny Rowe touched a bouncing ball through the Wimbledon line to Norwood, who fluffed his lines as he barely made contact with his attempt on goal.
Rod McDonald, the left-sided central defender of the visitors, had their first attempt as he lashed over from distance as the poor half continued.
Two corners, firstly from El Mizouni and then Dozzell, tested the Wimbledon defence, with Cole Skuse heading the latter's at goalkeeper Nathan Trott, before the first real chance came and went.
It was brilliant from Dozzell as the midfielder's pass from the centre-circle split the Dons' defence for Norwood to run onto, but the striker's dinked effort was well-saved by the trailing hand of Trott.
The visitors seemed content to pack midfield and remain solid but soon found themselves ahead as, after Janoi Donacien had been sucked inside as the Dons worked the ball from their right, full-back Guinness-Walker was on hand to lash the ball into the net.
Portman Road was stunned and the Blues had little by way of response before the half was out, with boos ringing out as the teams left the field.
They returned with Anthony Georgiou on the left wing, after he replaced El Mizouni, but the Blues had to soak up pressure for the opening few minutes of the second period.
Georgiou won a free-kick which he delivered, only for Luke Woolfenden's header to be blocked, before the Cypriot international winger fizzed in a low cross which Norwood couldn't quite reach.
Downes had two efforts fly over the bar, either side of Jackson replacing Dozzell, as the Blues improved without ever truly testing Trott.
Alan Judge was the next to enter the fray, replacing Danny Rowe, and it was the Irishman's corner which led to the equaliser as his delivery was superbly met by Norwood to level.
The visitors, who had been solid and disciplined throughout, were looking more and more nervy and those nerves told as Jackson fired home deep into stoppage time.
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