Ipswich Town will be on the road in the next round of the EFL Trophy after Ryan Clampin’s fluke goal ensured Colchester United will finish top of the group.
In a game in which the Blues had the better of things but didn't overly test home goalkeeper Ethan Ross, the left back rocketed a ball into the back of Tomas Holy's net as he simply looked to clear during a 50/50 challenge with Idris El Mizouni, just inside the Ipswich half.
And that is what ultimately separated the sides on a night when Ipswich only needed a draw to win their group, meaning they now face an away game in a regionalised last 32 next month.
Much of the build-up to this game centred around manager Paul Lambert's team selection, with the Scot promising he would give young players a chance to impress.
Brett McGavin was handed a senior debut in midfield while Ben Folami, who was held back from Australia Under 23 duty to play, was making his first start since recovering from a nasty Achilles injury suffered at the turn of the year.
El Mizouni was the other young player given a start, with the remaining outfield seven all 'qualifying players' under the EFL Trophy's selection criteria.
Three teenage substitutes were introduced in the final few minutes with midfielders Tommy Hughes, Liam Gibbs and Tawanda Chirewa all coming on. The latter is a Zimbabwean midfielder only 16 years and 31 days old, making him the second youngest player to represent the Blues, behind striker Connor Wickham.
The visitors, backed by a healthy following despite delays in the A12, started strongly and spent much of the opening 15 minutes in opposition territory, with El Mizouni having the first shot in anger as he rifled in an effort which Ethan Ross turned acrobatically over the top of the bar.
The Blues continued to push, with Folami nearly wriggling free in the box and Anthony Georgiou, making his second start in four days, testing home keeper Ross with a cross which the U's just about managed to clear behind for a corner.
Any attacks Colchester were able to muster, the Blues were able to snuff out at source, with captain James Wilson and Janoi Donacien looking particularly solid at the back.
There was a first-half flashpoint when Luke Norris left a late tackle on Toto Nsiala, which prompted the Ipswich defender to leap up and confront the Colchester striker, who in turn was booked.
The referee's card came out again a few minutes later when former Ipswich youngster Omar Sowunmi pulled Folami to the turf as the Aussie looked to break, but Ipswich were unable to make anything of the following free-kick.
Striker Folami was in the thick of the action again as he found space on the right and pulled the ball back for Gwion Edwards to drag a shot wide, before having a good shot of his own blocked over the bar by Luke Prosser as Ipswich worked the ball down the left through Georgiou.
The final effort of the half came from the hosts, as Norris whipped a free-kick into the side-netting after Clampin was brought down by Wilson 22-yards from goal.
Folami was again involved just 30 seconds after the interval as, after a burst forward by Emyr Huws, he twisted and turned inside the area and dragged the ball across the face of goal.
The same two players were involved again as Georgiou's cut-back caused chaos, before El Mizouni had a shot blocked behind for a corner which ultimately came to nothing.
Lambert tried to lift his team going into the final 20 minutes, urging his side to raise intensity levels, but he would not have anticipated for Clampin's thunderbolt fluke as the left back intercepted a ball ahead of El Mizouni and thumped the ball over the top of Holy and into the back of the net.
Youngsters Hughes, Gibbs and Chirewa were all brought on in the final minutes of the game, in which the Blues showed little sign of getting back into the game.
The draw for the next round will be made on Saturday at 2pm.
Col U: Ross, Lapslie, Prosser, Sowunmi, Senior (Poku 65), Pell, Norris, Brown, Sarpong-Wiredu (Jackson 57), Clampin, Nouble (Robinson 71)
Subs: Gerken, Bramall, Eastman, Stevenson
Ipswich Town: Holy; Donacien, Nsiala, Wilson, Kenlock; McGavin, Huws, El Mizouni (Hughes 87); Edwards (Chirewa 90), Georgiou (Gibbs 87); Folami
Subs: Norris, Woolfenden, K Brown, Chirewa, Rowe
Attendance: 5,104 (2,781 away fans)
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