Franck Queudrue has warned former club Fulham that he will put friendship to one side when Birmingham travel to Craven Cottage on Saturday.
The French defender spent a year with Fulham before signing for Blues last summer.
Both clubs are in the relegation zone with just two games of the season remaining, and they face each other in a crucial clash this weekend.
Victory for Birmingham would almost certainly send Fulham down but Queudrue insists there can be no room for sentiment.
"It's tricky to say which way it will go. I will be sad for my mates if we won, obviously. But this is my job," he said in the Daily Star.
"I have never been relegated and I have no friends when I step on the pitch, that's not a problem. I'm a professional.
"I enjoyed my time at Fulham but hopefully we can get the result we need."
Queudrue accepts that the match might not be the most attractive given the circumstances, adding: "We are in a bad position. We don't need to be pretty, we just need the points."
Birmingham were hammered 5-1 by Aston Villa in their last away match and let a two-goal lead slip as they were held by Liverpool on Saturday.
However, Queudrue is confident they can get back on track and clinch their survival.
"It's up to us to do something about it. I think it will be down to the side which holds its nerve best," he said.