Alex McLeish admits a lengthy injury list has taken its toll on Birmingham who face a last-day battle to preserve their Barclays Premier League status.
The Carling Cup holders are only above the bottom three on goal difference after a 2-0 home reversal against Fulham via Brede Hangeland's brace.
They were without eight players before kick off and lost four more - Lee Bowyer, Martin Jiranek, Alexander Hleb and Stuart Parnaby - during the game to end with 10 men.
Now Birmingham, who have won two of 11 matches since their cup triumph over Arsenal, have to ensure they match the results of Wigan and Blackpool to stay up when they visit Tottenham on Sunday.
McLeish said: "It is a tough task for us to go to Spurs and win but we've done it before.
"The evidence is there it can be done and it is about picking ourselves up and getting off the floor because that dressing room is hurting in there.
"It is a test of character. They have shown the character time and time again.
"I can't accuse them of not having character. It is there but we were out-muscled.
"They know that was not one of their best performances and they also know we now face a battle to retain Premier League status."
McLeish added: "I think you have to realise the amount of people we've got missing at a crucial stage of the season.
"I think any team would suffer with the amount of players we've had missing this season.
"But once we lick our wounds over the next couple of days, we will be bang at it.
"We've got to believe and I've been in situations before where it's looked impossible and it's worked and happened for us."
Fulham boss Mark Hughes praised his players for their response after being beaten 5-2 at home by Liverpool on Monday.
He said: "I was pleased to get the reaction I got. I didn't doubt the players in fairness.
"We found ourselves on Monday where we were 3-0 down and had to chase the game against a good side and they picked us off.
"At Birmingham, was about showing we hadn't switched off for the end of the season.
"We've got targets we set ourselves and we intend to reach them.
"We were fully focused and I think you can see that from the way we approached the game and we were able to get another away win which has been hard to come by.
"We've had back to back away wins so we've made a marked improvement in terms of what we can produce on the road."