Town’s EFL Cup run ended at the first round stage after Stevenage left Portman Road having picked up a deserved 1-0 win, Ben Kennedy scoring the winner in the 53rd minute.
Boss Mick McCarthy named a stronger than usual cup side, although still featuring seven changes from the team which beat Barnsley 4-2 on Saturday.
Dean Gerken was in goal with one-time Stevenage loanee Tommy Smith and Paul Digby at the heart of the defence and Jonas Knudsen and skipper Luke Chambers the full-backs.
In midfield Kevin Bru and Jonathan Douglas lined-up in deeper central roles behind Andre Dozzell, who was between them and striker Freddie Sears, with Conor Grant on the left and weekend hat-trick hero Grant Ward on the right. Last week’s two new signings were both making their full debuts.
Bartosz Bialkowski, David McGoldrick, Teddy Bishop, Christophe Berra and Cole Skuse were on a strong bench, while academy striker Ben Morris, 18, was named among the senior subs for the first time.
After a tentative first 10 minutes the visitors were the first to threaten, Tom Conlon crossing from the right and Luke Wilkinson looping a header over.
Town’s first opportunity came in the 16th minute when Dozzell sent Sears away on the right. The former Colchester man crossed towards Douglas, who stooped to head low past Stevenage keeper Jamie Jones’s right post.
Saturday’s star man Ward struck his first effort of the evening in the 25th minute but the ball deflected wide for a corner.
Two minutes later Boro’s Kennedy bludgeoned his way through a couple of tackles on the edge of the box but was unable to make significant contact with his shot and it failed to test Gerken.
On 33, with Town starting to look more dangerous, Sears was crowded out on the left. The loose ball fell to Knudsen but the Danish international screwed his volley well wide.
Bru sent Sears away on the right of the area with a clever pass three minutes later but the former Colchester man’s shot flew wide.
Knudsen burst away down the left in the 37th minute and crossed, but the ball hit Dozzell on the heel as he looked to volley goalwards. Soon after, Bru curled a freekick over after Grant had been fouled.
A minute before the break, Stevenage’s Conlon struck the first half’s only shot on target from a freekick just outside the area to the right. However, Gerken got down to his right to firmly punch the ball away from goal.
That was the last significant action of a not overly enthralling 45 minutes played in a pre-season atmosphere in front of Portman Road's lowest League Cup crowd for 20 years.
After a quiet start, the Blues gradually began to threaten sporadically but had failed to force Stevenage keeper Jones into a save.
McCarthy swapped Dozzell, who had rather drifted out of the game after a bright start, ahead of the second half as the Blues moved to 4-4-2.
Four minutes after the restart McGoldrick teed up Bru 20 yards out and the Mauritian international hit Town’s first shot on target. However, Jones was able to claim with relative ease.
Smith was booked in the 50th minute after bringing Kennedy down as he burst towards the area on the Stevenage right. The Blues’ centre-half was probably a touch unfortunate as the clash had appeared to be little more than a tangle of legs.
Gerken palmed Conlon’s freekick behind at his near post and from the resultant corner Chambers nodded Wilkinson’s header behind.
And from that flag-kick the visitors went in front. Town initially cleared but Charlie Lee won the ball off Ward as he looked to break. The former Peterborough man’s shot was deflected and the wrong-footed Gerken was only able to save with a toe and Kennedy stabbed home the rebound.
McGoldrick looked to hit back on 55, curling a strike from distance wide. The visitors made their first change six minutes later with Andrew Fox replacing Dean Wells.
Grant forced Jones into a save to his left with a powerful strike on 65 after a spell of Blues possession.
A minute later, Stevenage almost went two in front. Bru’s shot was blocked on the edge of the visitors’ box and Rowan Liburd spun away from Digby on halfway, leaving the centre-half in his wake. The striker burst into the area but Gerken quickly came off his line to block his shot.
Bishop replaced Bru for Town on 69, then two minutes later McGoldrick hit a well-struck shot which Jones palmed behind.
A mix-up between Knudsen and Gerken as the Dane sought to deal with a cross from the left almost led to an opening for Boro soon afterwards but the full-back was eventually able to clear. On 77 Lee was booked for a foul on Bishop.
Ward saw a shot blocked at one end, then Kennedy went well over from distance for the League Two club, whose skipper Ronnie Henry was booked for a foul on the former Spurs winger as the game moved into its final scheduled 10 minutes.
The Blues finally began to look more threatening, Grant and Knudsen saw shots blocked, then McGoldrick curled into Jones’s arms.
Another Ward strike was blocked and with two minutes left on the clock McGoldrick curled another effort wide.
Knudsen’s low cross from the left just wouldn’t fall for Ward, then after good work from the ex-Tottenham man Sears’s shot was blocked.
The fourth official signalled five additional minutes and soon after Digby flicked a header to Jones from a Knudsen cross.
Deep into injury time McGoldrick’s cross from the right fell to Bishop but he scraped his shot well wide.
That was the last action of Town’s 2016/17 EFL Cup campaign with Stevenage claiming a victory over the Blues at this stage of the competition for the second time in four seasons. It's the 10th time in 14 seasons that the Blues have gone out of the competition to opposition from a lower league.
Town never dominated the game in the manner that a Championship side - even one with seven changes - ought to do against a League Two team with the performance as flat as the atmosphere and there seemed little urgency until injury time.
While the Blues had opportunities, they were almost entirely shots from distance with no real clear-cut chances carved out, and even with the longer range efforts Stevenage keeper Jones was comfortable. The visitors might even have added to their lead but for Gerken’s save from Liburd.
Boss McCarthy’s cup record with Town now reads a mere two wins from 13 ties, both in this competition last season.
Town are next in action at Brentford on Saturday when they will be looking to add to Saturday’s 4-2 opening day victory over Barnsley and improve greatly on this evening’s display.
Town: Gerken, Chambers (c), Digby, Smith, Knudsen, Douglas, Bru (Bishop 69), Dozzell (McGoldrick 46), Grant, Ward, Sears. Unused: Bialkowski, Berra, Kenlock, Skuse, Morris.
Stevenage: Jones, Franks, Wilkinson, McAnuff, Liburd (Godden 71), Kennedy, Gorman, Wells, Lee, Henry (c), Conlon (Tonge 88). Unused: Day, Fox, Pett, Hyde, Donnellan. Referee: Charles Breakspear (Surrey). Att: 6,858 (Boro: 245).