Tyreece John-Jules netted in the seventh minute to give the Blues a 1-0 half-time lead over Southend United at Portman Road.
Town named an entirely changed XI with Vaclav Hladky in goal with a back four of, from the right, Kane Vincent-Young, Corrie Ndaba, Cameron Burgess and Greg Leigh ahead of him in a 4-2-3-1 system.
Rekeem Harper and Cameron Humphreys were the central midfield pair with Kyle Edwards, Sone Aluko and John-Jules behind lone central striker Kayden Jackson.
There was no place for new signing Leif Davis, who only returned from Leeds United's pre-season tour of Australia at the weekend, while everyone else aside from Dominic Ball and Idris El Mizouni were on the bench.
National League Southend, whose players had no numbers on the back of their shirts, were skippered by former Town academy scholar Nathan Ralph.
In the seventh minute Shrimpers midfielder Cav Miley was shown a yellow card for a foul on Vincent-Young and from the resultant free-kick, the Blues, wearing their red and black away kit, went in front.
Aluko sent the ball to the near post and John-Jules volleyed his second goal of pre-season past visitors’ keeper Steve Arnold.
Town, with former loanee and local boy Macauley Bonne sitting in the crowd, went close to a second in the 11th minute when John-Jules sent Edwards away on the right and crossed low and Aluko diverted it past the far post with Jackson at the back of the box appearing to have been who the winger was trying to pick out.
The Blues had been completely dominant from the start and as the game passed the quarter-hour mark were camped permanently around the Southend box winning a succession of corners.
On 21 Edwards won the ball on the Town right, brought it forward and inside before hitting a low shot which keeper Arnold did well to push past his left post.
Four minutes later, another sharp move down the right ended with Vincent-Young crossing and the ball being cleared ahead of John-Jules.
The on-loan Arsenal man went close to his second of the evening in the 33rd minute with a shot across Arnold from the right of the box which the keeper push past his right post.
Three minutes later Edwards again brought the ball in from the right and hit a shot straight at Arnold which the Southend man almost allowed to squirm between his legs. On 39 Aluko struck a low 25-yard effort which was too close to the Shrimpers keeper.
Southend had their first chance of the match in the 41st minute. Ralph appeared to take a dive as Vincent-Young made a challenge and the loose ball ran to Jack Bridge whose effort was blocked by Hladky and in any case the linesman’s flag had been raised.
Bury St Edmunds-based referee Chris Pollard’s whistle ended the half without further incident with the Blues having been in complete control from virtually start to finish.
Town had passed the ball around confidently and at pace and had created enough chances to be more than the single goal in front with John-Jules finishing deftly and putting in an impressive 45 minutes.
Town: Hladky, Vincent-Young, Burgess, Ndaba, Leigh, Harper, Humphreys, Edwards, Aluko, John-Jules, Jackson. Subs: Walton, Donacien, Penney, Edmundson, Morsy, Woolfenden, Burns, Evans, Ladapo, Harness, Chaplin, Chirewa.
Southend: Arnold, Ralph (c), Hobson, Kensale, Bridge, Husin, Dalby, Clifford, Taylor, Miley, Mooney. Subs: Andeng Ndi, Powell, Wood, Fonguck, Wreh, Benton, Demetriou, Davis, Crowhurst, Coker, Reeve. Referee: Chris Pollard (Bury St Edmunds).