The Welsh international blasted over a chance to put the Reds into the 4th Round at the expense of their Premier League opponents, instead Forest now face a replay sandwiched in between some vital league fixtures.
"His run up was too casual, but he's been brilliant for us this season," said boss Davies afterwards.
"It was too complacent for me but like I said, he's been brilliant for this football club and you have to take the good with the bad."
Blues boss Alex McLeish made some changes to his side and also saw Lee Carsley injured.
He commented: "I would have liked to have won it, but Forest had a lot to say about that.
"They had their chances and we also had our chances, but we'll take the draw. We're still in the cup."