The Blues and Leicester City remain locked at 0-0 at half-time at Portman Road.
Skipper Sam Morsy, Omari Hutchinson, Liam Delap and Ben Johnson all returned to the Town starting XI.
Morsy missed last week’s 4-3 defeat at Brentford due to a hamstring problem, but rejoined Kalvin Phillips in the centre of midfield.
Johnson, who had been out with a thigh injury, came in for Harry Clarke at right-back, with the former Arsenal youngster unavailable due to his red card last week.
Hutchinson was over the illness which sidelined him at the Gtech Community Stadium and started on the right with Conor Chaplin in the centre and Sammie Szmodics on the left. Delap got the nod ahead of former Leicester frontman George Hirst as the lone striker.
Hirst was among the subs alongside Jens Cajuste and Jack Clarke, who started last week, Nathan Broadhead, yet to appear for Town this season, and Massimo Luongo, back from an ankle injury.
Leif Davis was making his 100th appearance for the club at left-back and Cameron Burgess his 100th start for the Blues at the centre of the defence.
Leicester, whose manager Steve Cooper was serving a one-match touchline ban despite some confusion whether that was the case in the run-up to the match, made two changes from the team which lost 3-1 at home to Nottingham Forest last week with James Justin and Caleb Okoli dropping to the bench and Victor Kristiansen and Jannik Vestergaard coming into the XI.
The Foxes saw virtually all of the ball in the early stages and in the third minute created the first chance from which they will feel they should have scored.
Skipper Vardy was played in towards the right of the box and cut across towards Stephy Mavididi in space on the left breaking towards goal. Fortunately for Town, O’Shea got a touch and Mavididi hit the ball against his own foot and Aro Muric was able to claim.
Leicester continued to dominate and in the eighth minute Abdul Fatawu cut in from the right and hit a shot which Muric palmed away to his right for a corner.
Town went close for the first time in the ninth minute. Hutchinson stole the ball from Vestergaard after a poor touch on the edge of the area and crossed for Szmodics, who headed what was a difficult chance over.
On 11, Chaplin brought the ball in from the right and hit a shot wide following a neat exchange of passes on the right.
A minute later, Town claimed a penalty when Delap broke towards goal and appeared to be clipped by Vestergaard’s heel. VAR official Stuart Attwell took a look but opted not to award a penalty.
As the game reached the quarter-hour mark, with Leicester still largely in control of the game, Facundo Buonanotte skipped his way past a number of Blues defenders to work his way to the left of the box before hitting a shot which Muric batted away and Leif Davis cleared.
In the 21st minute, Davis curled over a corner from the left to the penalty spot where Phillips’s volley was blocked. The loose ball fell to O’Shea and the Irishman’s effort was also stopped.
From the resultant flag-kick, O’Shea claimed he’d been hauled down as he sought to get a head on Phillips’s ball but again referee Tim Robinson wasn’t interested. Play moved to the other end and Mavididi was penalised for fouling Phillips on halfway. Buonanotte was subsequently booked for kicking the ball away.
Town were taking charge and Hutchinson saw a curling effort from the edge of the box blocked, then saw a teasing cross headed away in front of Delap and Szmodics.
On 29, Delap brilliantly turned Wout Faes on halfway and brought the ball forward before finding Hutchinson on the right but the former Chelsea man’s cross was blocked and deflected behind off him for a goal-kick.
Within a minute, Town had their best chance of the afternoon up to that point. Davis’s deep corner from the right reached an unmarked O’Shea, who headed into the ground but over. The Irish international defender’s reaction showed he knew he should have scored.
Visitors keeper Mads Hermansen took an age over the goal-kick and was spoken to by the referee but not carded.
Hutchinson continued to be a threat on the right and in the 34th minute was found by Chaplin, the England U21 international’s strike deflecting behind for another corner.
From that flag-kick, the ball was won back by Phillips who brought it forward and eventually Chaplin found space but pulled his right-footed shot wide of Hermansen’s right post.
Town were by now well in control and in the 39th minute Chaplin came very close to a stunning first Premier League goal. The former Portsmouth man exchanged passes with Delap, then took the ball on and inside before shooting only inches away from the top corner.
Four minutes later, a slick Town move ended with Chaplin flicking a lofted pass through for Szmodics but Hermansen was able to punch away.
Soon after, with Town increasingly dominant and Portman Road upping the volume, Johnson side-footed an effort from the edge of the box towards the top corner but the Leicester keeper claimed.
On 44, Phillips was booked for a late charge on Buonanotte, who made a lot of the challenge. VAR looked at the incident following claims of an elbow but cleared the Town midfielder. While the Argentina international was receiving treatment, the fourth official’s board announced two additional minutes.
Neither side was able to create an opportunity in that time but the Town fans will have been the happier with their side at the break.
The visitors had started much the stronger - as they did in the two games between the teams last season - and should have gone in front via Mavididi early on.
But as the half progressed the Blues gradually began to take control and were well in charge in the last 20 minutes with O’Shea’s header Town’s best chance.
Chaplin and Hutchinson had been among the Blues’ best performers with the club’s record signing showing why there had been such a clamour for him to move out to the wing.
Town: Muric, Johnson, O’Shea, Burgess, Davis, Morsy (c), Phillips, Hutchinson, Chaplin, Szmodics, Delap. Subs: Walton, Woolfenden, Burns, Cajuste, Townsend, Luongo, Hirst, Broadhead, J Clarke.
Leicester: Hermansen, Pereira, Faes, Vestergaard, Kristiansen, Ndidi, Winks, Fatawu, Buonanotte, Mavididi, Vardy (c). Subs: Ward, Justin, Coady, Okoli, El Khannouss, Ayew, Skipp, Soumare, McAteer. Referee: Tim Robinson (West Sussex), VAR: Stuart Attwell (Nuneaton).