Tyler Dibling’s fifth-minute goal has given Southampton a 1-0 half-time lead over the Blues at St Mary’s.
Town made one enforced change with Jens Cajuste coming in for his full league debut for Kalvin Phillips, absent due to a minor thigh problem.
Cajuste joined skipper Sam Morsy in the centre of midfield with Jack Taylor coming onto the bench with the Blues’ 20 otherwise unchanged.
Southampton made four changes from last week’s 3-0 defeat at home to Manchester United with contract rebel Kyle Walker-Peters, Chelsea loanee Lesley Ugochukwu and Ben Brereton-Diaz all dropping to the bench, and suspended skipper Jack Stephens missing out.
Taylor Harwood-Bellis, Charlie Taylor, Adam Lallana and ex-Town loanee Ryan Fraser came into the team.
Flynn Downes, the Blues’ youngest-ever captain, skippered the Saints for the first time in Stephens’s absence following his red card last week. Former Blues loan keeper Alex McCarthy was on the bench.
Town started on the front foot taking the game to the home side and might well have gone in front in the second minute.
Wes Burns wafted a cross from the right towards the far post where Sammie Szmodics shot wide. It may have been a tight angle but the former Blackburn man will feel he probably should have done better.
From the goal-kick, Saints keeper Aaron Ramsdale played it out to Downes on the edge of the area, where the former Blues midfielder was out-battled by Cajuste, whose shot was saved by Ramsdale. However, referee Sam Allison had, somewhat harshly, awarded a free-kick against the Sweden international.
Despite Town having started the brighter, the home side took the lead in the fifth minute.
Axel Tuanzebe tried to play out from the back from inside his own area to the right having broken up a Southampton attack but found a Saints player. The ball was moved inside and Lallana played a pass in between Jacob Greaves and Leif Davis for 18-year-old Dibling, who confidently beat Aro Muric to claim his first Premier League goal.
Having gone behind to a poor goal from their perspective, the Blues set about getting back on terms, quickly restoring their early superiority.
On 12, Burns crossed from the right left-footed to Szmodics, who headed straight at Ramsdale and with the linesman’s flag subsequently raised.
Four minutes later, Omari Hutchinson, again playing in the centre of the three behind striker Liam Delap, sent a dangerous ball across from the right after a corner had been played to him at the corner of the box and the ball seemed to flash past both Szmodics and Greaves at the far post.
Aside from the goal, it had been all Town. On 20, Szmodics and Davis were both forced away from goal as they chased a pass looping to the left of the area.
From the resultant corner, the ball was half-cleared to Cajuste, who smashed a shot deep into the Southampton fans behind the goal.
Following the strike, Ramsdale was treated for what looked to be a tactical injury in order to upset Town’s momentum.
The break seemed to have its apparently intended effect with the Saints under less pressure and having some possession in the Town half.
On 25 Taylor was booked for a foul on Burns as the Wales international sought to bring the ball out on the right.
Two minutes later, Saints almost doubled their lead. Harwood-Bellis appeared to go through the back of Delap to win the ball on halfway before Dibling threaded a ball for Cameron Archer to chase down the middle.
Greaves and Muric did superbly to force the former Aston Villa man wide to the left and he eventually stroked the ball against the post, the Town keeper pouncing on it. VAR might have had something to say about it had it gone in given the challenge on Delap.
But Town restored their dominance as half-time approached and on 43 Burns hit a low cross-shot which was diverted out for a corner. From Davis’s very deep flag-kick, Greaves headed back across goal but Ramsdale plucked it out of the air.
Moments later, a Delap strike was blocked, then, seconds before the scheduled end of the half ahead of two additional minutes, Davis was found at the far post but his effort from a tight angle was forced out for the first of three corners.
From the second, the ball was again played short to Hutchinson at the corner of the box, the former Chelsea man cut in and hit a shot which was destined for the top corner until Ramsdale tipped it over.
That was the last action of a half during which the Blues had been well on top for the most part but without scoring.
Town had started strongly and didn’t allow Southampton’s very preventable goal to upset their rhythm.
The Blues had had a number of chances across the half, while Archer spurned a golden opportunity out of almost nothing to increase the home side’s lead.
Town will be aiming to maintain their overall dominance in the second half but while finding a cutting edge.
Southampton: Ramsdale, Sugawara, Harwood-Bellis, Bednarek, Fernandes, Downes, Taylor, Dibling, Lallana, Fraser, Archer. Subs: McCarthy, Walker-Peters, Wood, Ugochukwu, Aribo, Cornet, Armstrong, Stewart, Brereton-Diaz.
Town: Muric, Tuanzebe, O’Shea, Greaves, Davis, Morsy (c), Cajuste, Burns, Hutchinson, Szmodics, Delap. Subs: Walton, Johnson, Townsend, Luongo, Taylor, Chaplin, Ogbene, J Clarke, Hirst. Referee: Sam Allison (Wiltshire). VAR: Jarred Gillett (Australia).