Foster had been left unsighted by Scott Dann's positioning at his post but the goalkeeper was about to prove his worth to Birmingham by keeping them in the game with a series of stunning saves as West Ham produced wave after wave of attack in their bid to find a crucial second goal.
Wigan soon crafted a chance of their own after the lively Charles N'Zogbia escaped down the left, but from his pull-back ScottDann flung himself in the way of Rodallega's shot.