Alex McLeish has brushed off suggestions that Birmingham would have secured Premier League safety by now had Steve Bruce remained with the midlands club.
And the former Scotland boss believes even Sir Alex Ferguson and Jose Mourinho may have faced an uphill struggle to keep Blues in the top flight had they taken charge when he did in December.
Bruce and his assistant Eric Black quit City in late November after becoming fed up with the uncertainty surrounding the club regarding the possible takeover by Carson Yeung which eventually never materialised.
At that stage Birmingham had collected 11 points from 14 games and since then under McLeish have taken 21 points from 23 matches.
McLeish, whose side entertain Blackburn on Sunday, said: 'I can't control what anyone else has said. That is hypothetical stuff.
'Steve Bruce could have stayed and taken Birmingham clear of trouble. That is definitely a possibility. But equally they could have been adrift.
'The challenge for me was to improve things and hopefully by the end of the season steer clear of relegation.
'Steve may have done that but it is all guess work and no-one can say for certain that is the case.
'Is it being disrespectful to you? I can't control that. I can't tell people what not to say. I can't say 'please don't say that, you'll hurt my feelings.' I can't control what others say.
'I've got to focus on the outcome for me, what my challenges are, and what my goal is.'
McLeish added: 'I don't think you can judge me until I get some time in the job.
'If Sir Alex Ferguson and Jose Mourinho came into this job from December-January until now, you couldn't say they would have got the club clear of relegation. You couldn't say that for sure.'
City have to beat Blackburn and then hope that Fulham and Reading fail to win away to Portsmouth and bottom club Derby respectively.
McLeish said: 'It now comes down to the very last game. When I came in, I said this looks like a battle to the end and that's what we find ourselves in to the very last day.
'It is exciting, nerve-wracking. I am looking forward to it. I'd rather it was tomorrow because the waiting is the worst part about it. We'd like just to get on with it and get it done.
'As a manager, I was relegated with Hibernian but it wasn't the end of the world. It could be the beginning here but, as I said, I'm focused on another outcome - Blues staying up.'
City will be looking for their first six in six matches and then hope the footballing gods will be smiling on them at Fratton Park and Pride Park.