Gary Rowett's men's next opponents currently find themselves in the Championship relegation zone.
Birmingham goalkeeper Tomasz Kuszczak insists that the club's toughest games come against the sides that are fighting for their lives towards the bottom of the Championship table, the Birmingham Mail reports.
The Blues face second-bottom side Bolton on Tuesday, and ahead of the game, Kuszczak explained that while it may be easy to assume that Gary Rowett's men will be overwhelming favourites against the Trotters, these kind of games present challenges that make the outcome a lot more difficult to predict.
"It's really tough football, it's not beautiful football. If somebody thinks 'We are here and they are there at the bottom, it's going to be easy' - they are wrong. It's harder," he told the Mail.
"Playing against teams like that is always difficult, they fight, they run an extra hundred yards in the game, they jump two inches higher than everyone else, they throw themselves around, they try to survive. It's instinct.
"We can see it's difficult in our results."
Birmingham - who are currently in the top half of the division - have had a good record against the sides above them in the table, having beaten both Derby and Ipswich 3-0 recently, but have been much more disappointing against the teams trying to avoid relegation.
Their victory over Neil Lennon's men in October remains the only time that the Blues have beaten one of the sides in the bottom three, with one draw and two defeats coming in the other games against those currently in the relegation zone.
But while improving their poor record against the bottom three may prove a motivating factor for Rowett's men when they meet Bolton, the prospect of moving to within two points of the play-off places will surely be the thing that drives the club to try and get the three points.