Will Keane’s first Blues goal has given Town a 1-0 half-time lead over Rotherham United at Portman Road.
New signings Collin Quaner and James Collins were handed their Blues debuts and Keane and Callum Elder their Town league bows and their first appearances at Portman Road having played at Accrington last week.
Collins joined skipper Luke Chambers at the centre of the defence with Pennington at right-back and Elder on the left.
Cole Skuse was back after his knee injury with Trevoh Chalobah at the heart of a four-man midfield.
Jack Lankester was on the right with Freddie Sears on the left, while Keane started behind Quaner up front.
Emyr Huws returned to the bench having been out for 13 months alongside Town’s fifth new signing Simon Dawkins. For Rotherham, ex-Blues keeper Lewis Price was on the bench.
Town had most of the ball in the early stages but without creating a serious chance. On 10 captain Chambers took what looked a nasty fall over the perimeter wall into the stand having seen the ball out of play ahead of Millers’ striker Michael Smith but was quickly back on the pitch.
Visitors’ defender Zak Vyner was shown the game’s first yellow card in the 13th minute for shoving Sears. The Millers struggled to clear the ball from the resultant freekick but the set piece ultimately came to nothing.
Town similarly took their time to clear a Rotherham set play on 18 but eventually broke quickly with Chalobah finding Keane on the left with a cross-field pass.
The on-loan Hull City man laid the ball back to Skuse, who struck a shot which deflected off one Millers player onto another’s arm. Referee James Linington waved away the Blues’ ambitious appeals for a penalty.
Lambert’s much-changed Town increasingly dominated but without being able to carve out a chance until the 31st minute when they took the lead.
Keane fed Sears wide on the left and the ex-West Ham man crossed back towards the one-time Manchester United trainee six yards out. The ball got away with him from his first touch but it came back to him off a defender and having taken a touch he lashed his first Blues goal into the net before celebrating in front of the Sir Bobby Robson Stand.
The game was subsequently held up for a long spell as Smith and Chambers, presumably due to his early tumble over the fence, underwent treatment. Soon after play had restarted, Rotherham’s on-loan Norwich defender Sean Raggett was replaced by Ryan Williams.
There was a scare for the Blues in the 43rd minute when Collins headed an Anthony Forde freekick from deep on the right against former Blues trialist Semi Ajayi and the ball looped wide.
A minute later at the other end, Sears hooked a shot over from a tight angle in the aftermath of a Lankester corner on the left.
Rotherham ended the half strongly, Joe Mattock hitting an effort from distance which Blues keeper Dean Gerken saw past his left post.
During three minutes of injury time Skuse was booked for a foul on Williams inside the centre circle.
Not long after, the half-time whistle was greeted by applause and cheers from the Portman Road support after an entertaining period with Town deserving to go in ahead.
The new look Blues had certainly looked to have more potential going forward than they had prior to the transfer window opening with Quaner adding a significant physical presence and Keane bright and inventive on the ball.
However, up until the goal, which Keane tucked away clinically at the second attempt, they had been unable to carve out a chance.
They had moved the ball around confidently, although while also showing some raggedness at times, perhaps inevitably given the number of changes to the team.
At the other end Collins had added composure and assurance on the ball to the backline. Rotherham failed to register a shot on target, although they had one or two occasions when they might have made more of openings inside the box.
Town: Gerken, Pennington, Chambers (c), Collins, Elder, Skuse, Chalobah, Sears, Lankester, Keane, Quaner. Subs: Bialkowski, Harrison, Bishop, Downes, Nsiala, Huws, Dawkins.
Rotherham: Rodak, Vyner, Raggett (Williams 37), Robertson, Mattock, Ajayi, Forde, Vaulks, Wiles, Taylor, Smith. Sub: Price, Ihiekwe, Wood, Jones, Palmer, Yates. Referee: James Linington (Newport IoW).