Ellis Harrison’s first goal for the Blues equalised Felipe Anderson’s opener for West Ham with Town and the Hammers level at 1-1 at half-time.
Striker Martyn Waghorn was again named on the bench, while Cole Skuse was missing due to the thigh problem.
In boss Paul Hurst’s first game as Town boss at Portman Road, Bartosz Bialkowski started in goal with Jordan Spence at right-back, Luke Woolfenden at centre-half alongside skipper Luke Chambers and Jonas Knudsen at left-back.
In midfield, Flynn Downes and Andre Dozzell took up the deeper roles with Tristan Nydam ahead of them, while Gwion Edwards and Freddie Sears were the widemen and Ellis Harrison the lone striker.
New loanee Trevoh Chalobah, who returned from the U19s Euros in Finland yesterday, is alongside another new addition Jordan Roberts and Waghorn among the subs.
Former Blues loanee Mark Noble was on the bench for the Hammers, while ex-Town left-back Aaron Cresswell missed out with a groin strain.
The Hammers quickly began to play the ball around confidently and went in front with the first attack of the game in the third minute.
Ryan Fredericks was sent away down the right by Andriy Yarmolenko before crossing and midfielder Felipe Anderson, who joined West Ham for £40 million from Lazio earlier this month, rose unmarked to nod into the corner of the net to Bartosz Bialkowski’s right.
While it was a perfectly-placed header, Blues boss Hurst will be unhappy with the defending and Bialkowski may also feel he ought to have got down to it.
The game continued in the same pattern with the Premier League side dominating possession, although without threatening again, but Town gradually began to see a bit more of the ball.
On 10, a Dozzell freekick was nodded down at the far past by Chambers but the skipper had strayed offside and in the 15th minute the Blues equalised.
Dozzell spotted Harrison’s run between two West Ham defenders and played a sublime through ball and the £750,000 signing from Bristol Rovers nonchalantly poked past Lukas Fabianski in the West Ham goal.
Harrison’s first goal in a Blues shirt gave Town confidence and they might have gone in front in the 19th minute when Sears, playing against his old club, fed Edwards in space just outside the box. The Welshman took the ball into the area but shot too close to Fabianski.
The Blues, who had dominated having netted their equaliser, went even closer on 24 when Sears crossed for Harrison, who evaded the West Ham offside trap and nodded past Fabianski, but off the Polish keeper’s right post.
A minute later, a frustrated Jack Wilshere was booked for fouling Downes with the Blues’ trio of teenagers in midfield more than holding their own and with the previously noisy Hammers fans now somewhat quieter.
Town continued to present the greater threat. On 33 Edwards seized on an overhit cross from the left and sent the ball back into the box. Harrison could only flick it on, but Sears teed-up Knudsen on the edge of the box from where the Danish international hit a powerful shot not too far over.
A Woolfenden misjudgement put the Blues under a spell of pressure as an entertaining half moved into its final 10 minutes and the Hammers began to look more threatening as the break approached.
After the Blues had repelled a series of corners, Wilshere’s clever ball played in Yarmolenko but the Ukrainian was crowded out by Bialkowski and Woolfenden.
Moments before half-time Sears struck a shot from distance which was too close to Fabianski.
The Blues were warmly applauded off at the break having impressed after a slow start when they perhaps showed their top flight opponents too much respect.
Even during that spell Hurst’s side showed their energy and pressing but once they had settled following West Ham’s goal they passed the ball around confidently with the midfield trio, 19-year-olds Dozzell and Downes and 18-year-old Nydam getting the better of their more illustrious opponents.
Dozzell’s pass and Harrison’s run and finish were the half’s highlight from a Town perspective but the Blues could well have gone in ahead with the former Wales U21 international unlucky with his header which struck the post.
Town: Bialkowski, Spence, Woolfenden, Chambers (c), Knudsen, Downes, Dozzell, Nydam, Edwards, Sears, Harrison. Subs: Gerken, Chalobah, Waghorn, Lankester, Ward, Roberts, Clements, Emmanuel.
West Ham: Fabianski, Fredericks, Ogbonna, Balbuena, Masuaku, Obiang, Kouyate, Wilshere, Yarmolenko, F Anderson, Arnautovic (c). Subs: Adrian, Zabaleta, Diop, Rice, Noble, Haksabanovic, Cullen, Martinez, Snodgrass.