Town's pre-season friendly at Cambridge remains 0-0 at the break.
Adam Webster made his first start in a Town shirt and Daryl Murphy his first start of pre-season, while David McGoldrick was on the bench having recovered from the hip injury which has kept him out of the previous three friendlies.
Manager Mick McCarthy named a team largely made up of the players who came on for the final half hour or so at Colchester on Wednesday.
Keeper Dean Gerken missed out with a hamstring injury and Michael Crowe took his place on the bench.
Second-year scholar Flynn Downes and first-year Tristan Nydam, both midfielders, were also included as cover with the U21s having been in action at Coggeshall on Friday night.
Town had most of the ball in the early stages without creating a significant opportunity, aside from two corners.
In sweltering conditions it was Cambridge who hit the game’s first shot in the 10th minute but George Maris’s low drive failed to significantly test Bartosz Bialkowski.
The Blues had the ball in the net in the 15th minute but with the linesman’s flag having been raised.
James Blanchfield, playing wide on the left with Teddy Bishop again on the right, fed right-back Josh Emmanuel, who chipped over a cross which Murphy headed goalwards. Cambridge keeper Will Norris palmed the ball away and Shane McLoughlin tapped in from close range but having strayed offside.
Town continued to have most of the ball but without creating many further chances. On 22 Murphy hit a shot on the turn just past Norris’s left post.
Four minutes later Luke Hyam required treatment after twisting his knee as he fell and after briefly carrying on was replaced by Nydam, making his first appearance for the first team.
Just prior to the first-year scholar’s introduction Cambridge weren’t far away from going in front. Joe Pigott beat Christophe Berra in the air and nodded down to Maris, who shot just past Bialkowski’s right post.
The U’s should have gone in front in the 44th minute when Emmanuel lost the ball in the Cambridge half and a long Greg Clarke ball sent Maris in on goal on the left. The striker took the ball round the advancing Bialkowski stroked it against the outside of the post.
That was the final action of a first half in which the Blues probably should have been behind with Maris having failed to take two decent chances with the one before the break easier to score than miss.
Town had kept the ball well at times but without creating many opportunities. Murphy’s header prior to McLoughlin’s disallowed effort having been their best chance.
Town: Bialkowski, Emmanuel, Knudsen, Hyam (Nydam 34), Webster, Berra (c), Bishop, Skuse, Murphy, McLoughlin, Blanchfield. Subs: Crowe, Chambers, Digby, T Smith, Kenlock, Dozzell, Bru, Douglas, Sears, Pitman, McGoldrick, Stewart, Malarczyk, Downes.