The Blues are still the best-placed team from the six that now realistically face the threat of relegation, but with the teams below them picking up points with increased regularity, they are by no means safe yet.
Indeed, due to results on Good Friday and Easter Saturday, including their own 1-0 defeat at the hands of out-of-form Nottingham Forest, they are now just one point clear of the bottom three and could end Monday in the drop zone should events conspire against them.
However, the likes of Doncaster Rovers, Millwall and Charlton Athletic are all still more vulnerable to relegation than Lee Clark's side, who have the luxury of a game in hand over the majority of the teams below them, as well as superior goal difference.
Recent wins over Millwall and Doncaster have aided their cause greatly, but it will be a concern that they no longer have any of their relegation rivals left to play this season.
It will also be a worry for Birmingham that three of their remaining four matches come at St Andrew's, where they have struggled to date. Their tally of 14 points from 20 games is the worst home record in the division and less than half as many points as they have managed to amass on the road this season.
They have not won in front of their own fans in the league since October, a woeful run of 15 matches, while they have only picked up two points from the last 24 available.
They will have no Lee Novak to call upon in their attempt to improve that statistic, while Paul Robinson is suspended for three matches, having picked up his 15th yellow card of the season against Forest.
Blackburn, meanwhile, find themselves just four points off the playoffs but are unlikely to launch a late push for the top six with a number of teams far better placed than them.
Draws have been their biggest problem in recent weeks, with six from their last nine outings, although they are unbeaten in that time and have not lost a game since March 12.
They have also kept three clean sheets in their last four games, which is a positive aspect for Gary Bowyer to focus on ahead of an anticipated playoff challenge next season.
He will not give up on reaching the top six in the current campaign until it is mathematically impossible, though, and victory on Monday could put them right in the mix should other results go their way.
They have two away fixtures left this season against teams struggling against the drop, and they have been good on the road recently, losing just one of their last eight.
Possible starting lineups
Birmingham: Randolph; Packwood, Caddis, Ferguson, Hancox; Thorpe, Curke, Spector, Reilly; Huws; Zigic
Blackburn: Robinson; Kilgallon, Evans, Hanley, Lowe; Keane, Conway, Williamson, Cairney; Gestede; Rhodes
Sports Mole says: 1-1