Town’s East Anglian derby against Norwich City at Carrow Road remains 0-0 at half-time.
Boss Mick McCarthy switched the Blues to a 3-5-2 formation with Adam Webster joining skipper Luke Chambers and Cameron Carter-Vickers at the back.
Dominic Iorfa came in for Jordan Spence in the right wing-back role with Jonas Knudsen on the left as manager Mick McCarthy eschewed his usual 4-3-2-1 system.
Stephen Gleeson was part of a three-man midfield with Cole Skuse and Callum Connolly with Joe Garner and Martyn Waghorn up front.
Spence, Bersant Celina and Grant Ward dropped to the bench alongside David McGoldrick, who was back after his knee injury. Sub keeper Michael Crowe was also among the subs having got over the illness which made him a pre-match doubt.
There was no place on the bench for Freddie Sears, although the former Colchester United man was in the travelling party.
The Canaries lined up in their usual 3-4-3 formation and were unchanged from the team which drew 1-1 at Derby County last week.
At a sunny Carrow Road on what would have been Sir Bobby Robson’s 85th birthday, Town won an early corner on the right.
Waghorn’s flag-kick was dealt with not entirely comfortably by the Norwich defence but the former Sunderland man’s subsequent ball back into the box was too long and Webster was unable to stop it going out of play.
Town made a positive start and they might well have gone ahead in the ninth minute via a familiar derby source.
Gleeson wafted a ball towards Norwich keeper Angus Gunn’s right post towards Knudsen, a scorer in each of last season’s derbies, who headed wide when he will feel he should have hit the target.
Moments later, Gunn was forced into his first serious save of the afternoon, the on-loan Manchester City man diving away to his right to palm Waghorn’s 20-yard shot wide.
Norwich had their first sight of goal in the 15th minute, but Nelson Oliveira’s touch let him down after he had been found by a clever pass over the top. The ball ran loose on the left but the Portuguese frontman’s cross was too long.
In the 18th minute, Garner looked to have sent Waghorn away on goal but Grant Hanley did well to get across and force the Town striker off the ball inside the area. Waghorn claimed a penalty but referee David Coote wasn’t interested, probably correctly.
Town had looked the more threatening side in the game’s opening quarter. The Canaries had had a fair amount of the ball but to little effect. On 22 Oliveira scuffed wide from distance.
James Maddison, the scorer of the only goal when the sides met at Portman Road in October, struck his first effort of the game just after the half-hour mark but his 25-yard freekick was watched past his left post by Blues keeper Bartosz Bialkowski.
Connolly did better with a freekick at the other end in the 33rd minute. His low strike was saved by Gunn down to his left but the keeper couldn’t hold on. Garner looked looked to get on to the loose ball at a tight angle on the right, Jamal Lewis barged into him and sent him to ground but referee Coote waved away the Blues’ striker’s protests.
Josh Murphy flashed a shot wide for the Canaries, then Knudsen saw a strike blocked on the edge of the Norwich box.
Gunn was forced into another save in the 40th minute. Following good work from Gleeson and Iorfa on the right, Waghorn found space to shoot on the edge of the box, the ball looping up into the six-yard box from where Connolly forced Gunn into another save.
The on-loan Everton man will have felt he should have had the ball in the net, but the linesman’s flag was raised in any case.
The Norwich keeper was forced into a more meaningful stop in the 44th minute when a 25-yard freekick was played short to Waghorn and the striker smashed a low strike which the keeper did well to get across to and paw behind.
Just before the break, Iorfa went to ground in the area after losing control of the ball as he burst into the box, much to the annoyance of Timm Klose, who shoved the Blues defender and was subsequently spoken to by the referee.
Town went off the happier of the two sides having had all the first half chances with Bialkowski still to be seriously tested.
Knudsen’s early header was probably the best opportunity, while Waghorn, twice, and Connolly had both stretched Gunn into making saves.
The Blues will probably feel they ought to have made more of their numerous set pieces - both freekicks and corners - with Waghorn’s balls into the box not always as dangerous as they have been at times in previous games.
At the other end, the Blues’ three-man backline had been comfortable for the most part, while Gleeson was starting to see more of the ball in midfield towards the end of the half.
Norwich: Gunn, Hanley, Zimmermann, Klose, Reed, Tettey (C), Leitner, Lewis, Maddison, Murphy, Oliveira. Subs: McGovern, Pinto, Stiepermann, Vrancic, Watkins, Hernandez, Srbeny.
Town: Bialkowski, Carter-Vickers, Chambers (c), Webster, Iorfa, Skuse, Connolly, Gleeson, Knudsen, Waghorn, Garner. Subs: M Crowe, McGoldrick, Celina, Spence, Ward, Hyam, Carayol. Referee: David Coote (Nottingham).