Birmingham City were unsuccessful with a late bid to sign defender Liam Ridgewell from local rivals Aston Villa.
Following Matthew Upson's deadline day departure to West Ham, Blues boss Steve Bruce had hoped to bring in Ridgewell as his replacement.
However, Martin O'Neill instantly rejected Birmingham's approach, with the Villa manager keen to hold onto the stopper.
"I am trying to build a squad here - not dismantle one," O'Neill said.
A big part of O'Neill's build is striker Shaun Maloney, who moved to Villa Park just before Wednesday's transfer deadline.
Maloney's Celtic deal was due to expire in the summer and O'Neill had expected the 24-year-old to sign a new contract with the SPL Champions.
But after making a late bid to sign the Scottish international, O'Neill was pleased to be able to push the deal through.
He added: "Shaun was out of contract in the summer, and we left it late before we even went in for him because I honestly thought he would sign a new contract at Celtic.
"But we were very encouraged with the way things progressed once we knew Shaun wanted to come and sign. We agreed everything with Celtic, and then it was simply a race against time - which we managed to win thankfully.
"He is a very decent player - not only during my time with him at Celtic - and he has done excellently in the last couple of seasons and has featured for Scotland.
"Shaun is an excellent player, and I think he is as conscientious as they come. He will be a big asset to this club, I have no doubts about that."