Alex McLeish is concerned Birmingham's push for cup glory on two fronts may take its toll on his ultimate goal - Barclays Premier League survival.
Blues will contest the Carling Cup final next weekend and are also through to the quarter-finals of the FA Cup after disposing of Sheffield Wednesday 3-0 at St. Andrew's on Saturday.
McLeish said: "It is great to be involved in the cup competitions at this stage. But I hope it doesn't take its toll in terms of our premier goal, which is Premier League status. My big craving is the Premier League. We definitely don't want the cup runs to take the steam out of the players."
He added: "I know they have got enormous character but, when I look back at the last league game against Newcastle, we looked flat and short of inspiration.
"That is always the danger, that the longer the season goes, some minds become tired as well as the bodies. I think mental tiredness is the biggest concern.
"That's why being able to recharge the batteries of a few of them this weekend was a Godsend.
"We left out a few players for next week's final which should benefit us."