Stephen Dobbie’s 23rd minute goal sees the Blues trailing 1-0 at half-time at Blackpool.
Boss Mick McCarthy was forced into three changes with Tommy Smith unavailable due to international commitments, Aaron Cresswell suspended and Paul Anderson out with a groin injury.
Tyrone Mings started at left-back, Luke Chambers moved into the centre alongside Christophe Berra for the first time, with midfielder Cole Skuse switching to the right-back role he previously occupied while at Bristol City.
Ryan Tunnicliffe moved into the centre of midfield with Jay Tabb coming in on the left, while skipper Carlos Edwards returned on the right.
New signing Stephen Hunt was amongst the subs, along with Anthony Wordsworth for the first time in a few weeks.
Blackpool included ex-Town loanees Bradley Orr, at left-back, and Ricardo Fuller from the start, while Michael Chopra was on the bench.
Fuller turned an early Stephen Dobbie cross into Dean Gerken’s arms, then Daryl Murphy chased a Skuse ball down the right but could only find Seasiders’ keeper Matt Gilks’s arms with his ball into the box.
Almost immediately, Gerken was out quickly to clear ahead of Fuller in a lively first five minutes.
The game became a cagier affair and neither keeper was troubled until the 14th minute when Gerken was required to come out of his area to nod a ball down the middle clear ahead of Tom Ince.
Town eventually cleared a Blackpool freekick into the box, Mings lashing clear moments before David McGoldrick escaped on the right but shot across the face of goal.
The Blues were close to going in front in the 20th minute when, after good work from Skuse, Edwards and Hyam, Murphy crossed low from the right. The ball ricocheted around home side’s area before falling to Tunnicliffe, who seemed certain to net his first senior goal from eight yards until a defender deflected his shot wide.
But it was Blackpool who would score the game’s first goal in the 23rd minute. Bobby Grant crossed from deep on the left and Dobbie broke into the area untracked behind the Blues backline and nodded across Gerken and into the net.
The Seasiders almost went two in front on the half hour when Grant got past Skuse on the Blackpool left — although was fortunate not to be penalised for pulling back the defender — and hit a well-struck shot which Gerken did superbly to divert over the bar. Soon after, Dan Gosling shot well wide from distance.
McGoldrick curled a 25-yard freekick well wide in the 43rd minute but Town weren’t looking particularly threatening, seeming lacking in ideas when penetrating deeper into Blackpool territory.
Murphy screwed a McGoldrick knockdown out for a throw shortly before the end of scheduled time, summing up the Blues’ lack of threat during the first period.
The whistle went with the home side deservedly in front. The Blues had had a fair amount of the ball but without significantly threatening.
Mick McCarthy is unlikely to be impressed with his defence allowing goalscorer Dobbie a free header in the manner that they did.
Town: Gerken, Skuse, Chambers, Berra, Mings, Edwards, Hyam, Tunnicliffe, Tabb, Murphy, McGoldrick. Unused: Loach, Hewitt, Veseli, Hunt, Wordsworth, Nouble, Taylor.
Blackpool: Gilks, Bishop, Broadfoot, MacKenzie, Orr, Gosling, Angel, Dobbie, Grant, Ince, Fuller. Unused: Warner, Blackett, Zeegelaar, Delfouneso, Chopra, Davies, Tyson. Referee: Iain Williamson (Berkshire). Att: