Town’s opening game of the season against Birmingham at Portman Road remains 0-0 at the break, however, an injury sustained by Andre Dozzell late on in the period overshadowed the half.
Joe Garner and Dominic Iorfa were given their Blues debut as Town lined-up in a surprise 3-5-2 formation.
Iorfa, on loan from Wolves for the season, started at right wing-back with Jonas Knudsen on the left and Jordan Spence, skipper Luke Chambers and Tommy Smith the central three.
In central midfield, Cole Skuse was joined by Dozzell and Grant Ward with Garner and Sears up front.
David McGoldrick and Bersant Celina were both on the bench having been ill for last week’s 6-1 friendly defeat at Charlton, while midfielders Flynn Downes, 18, and Tristan Nydam, 17, were also among the subs.
Birmingham, who lined-up 4-4-2, handed debuts to former Town loan keeper David Stockdale, who joined after turning down a new deal with Brighton, Marc Roberts, who signed from Barnsley, and Cheikh Ndoye, a recruit from Angers.
A torrential downpour preceded kick-off and rain continued to fall persistently as the game got under way.
Birmingham made most of the early running but without creating an opportunity until left-back Jonathan Grounds, a scorer in the 1-1 draw between the sides at Portman Road in April, hit a weak shot through to Bartosz Bialkowski in the fourth minute.
Soon after, as the sun broke through the clouds, Dozzell brought the ball forward from midway inside the visitors’ half but hit his effort well wide.
The Midlanders weren’t far from going in front on 10 when a long throw from Grounds on the left reached Clayton Donaldson, whose header was too close to Bialkowski who saved. A couple of feet either side of the keeper and Harry Redknapp’s side would have been in front.
Birmingham continued to have the better of it and just after the quarter hour right-back Emilio Nsue hit a low shot which Bialkowski claimed comfortably.
Town threatened for the first time from a Ward corner on the right. The ball eventually fell to Garner, whose shot deflected off a defender through to Stockdale.
The Blues began to get more into the game and in the 21st minute Ward, a debut hat-trick hero on the opening day a year ago, exchanged passes with Garner and broke into the area but put the ball wide from a very tight angle on the left of the area as Stockdale advanced.
On 26, following the latest in a succession of long throws from the right, Bialkowski saved Marc Roberts’s low shot from the right.
A minute later there was a further scare for the Blues when Iorfa looked to head a cross from the right behind and Knudsen, as he sought to avoid a corner, nodded the ball back to a Birmingham player on the right. Eventually it reached Che Adams on the left just outside the box, from where he curled a shot just over.
The visitors continued to look the more dangerous team and on 33 David Davis hooked a ball over as Bialkowski advanced having got in behind the backline, although Smith had looked to be fouled earlier in the build-up.
Bialkowski had to be on his mettle again in the 40th minute when Donaldson was played in on goal following a swift interchange of passes around the edge of the area, the Pole claiming at the former Crewe and Brentford striker’s feet.
Two minutes later, Dozzell played in Sears on the right of the box and the striker’s shot deflected wide.
From the corner, Dozzell went to ground clearly in pain as he challenged with a Birmingham player and subsequently underwent lengthy treatment for what appeared to be a knee injury before being stretchered off.
The 18-year-old, who had previously been treated for a knock a few minutes earlier, had been behind Town’s more threatening moments going forward and had been becoming more influential.
Downes replaced the England U19 international in the centre of the three-man midfield, making his senior debut.
There was just time for Donaldson to shoot wide past an empty goal with Bialkowski well off his line - an offside Birmingham player having blocked off a Town defender as he looked to get back - before referee Tin Robinson ended the half.
The visitors had been on top for the most part and had created the half’s better opportunities.
Town had threatened only rarely with Dozzell having been behind their few chances. Concerns regarding the extent of the academy product’s injury dominated the half-time chat around Portman Road.
Town: Bialkowski, Spence, Chambers (c), Smith, Iorfa, Ward, Skuse, Dozzell (Downes 45), Knudsen, Sears, Garner. Subs: Gerken, Webster, McGoldrick, Celina, Nydam, Kenlock.
Birmingham: Stockdale, Nsue, Grounds, Morrison (c), Roberts, Davis, Gardner, Ndoye, Maghoma, Donaldson, Adams. Subs: Kuszczak, Shotton, Kieftenbeld, Keita, Brock-Madsen, Harding, Gleeson. Referee: Tim Robinson (West Sussex).