The Blues have won back-to-back matches to move up to 19th and just one point behind opponents Forest, who are winless in their last two games.
Birmingham looked in serious trouble after losing 3-0 to Bristol City on March 13, a result that left them three points above the relegation zone, having played four games more than Rotherham United directly below them.
That defeat proved a turning point in their campaign in many ways, though, as Aitor Karanka was sacked soon after and replaced with Lee Bowyer, who has done a brilliant job in his first month in charge.
The Blues have won four, drawn one and lost one of their opening six matches under former Charlton Athletic boss Bowyer, including back-to-back victories without conceding.
Birmingham beat Stoke City 2-0 last week and followed that up with a 1-0 win at Rotherham on Sunday - Harlee Dean scoring late on at the New York Stadium to give his side a nine-point gap on the bottom three.
Rotherham still have two games in hand, but there are now enough teams between the Blues and the Millers for Bowyer to sleep a little easier.
Forest are in a similar position to Birmingham, meanwhile, insofar as they are effectively now safe but cannot take anything for granted just yet.
The Reds lost 2-0 at home to Huddersfield Town on Saturday to make it back-to-back games without scoring, having previously played out a 0-0 draw at Bristol City.
Chris Hughton's charges are 10 points better off than 22nd-placed Rotherham, although that could potentially become a four-point margin should the Millers win their games in hand.
Forest have only suffered two defeats in their last 12 away league games, though, winning half of those and keeping a clean sheet in both of their last two on the road.
However, Birmingham have won all three of their home league games under Bowyer, who could become the first City boss since Dave Mackay in 1989 to win his first four at the helm.
Scott Hogan was a late substitute for Birmingham in their win against Rotherham and is in contention for a first start since the stalemate with Brentford at the start of the month.
Ivan Sanchez, another of Birmingham's substitutes last time out, is also pushing for inclusion.
Striker Glenn Murray has scored six goals in his last six appearances against Birmingham in all competitions, but he has had to settle for a back-up role of late.
Birmingham City possible starting lineup:
Etheridge; Dean, Roberts, Pedersen; Colin, Sunjic, Gardner, Seddon; Sanchez; Hogan, Jutkiewicz
Nottingham Forest possible starting lineup:
Samba; Christie, McKenna, Worrall, Blackett; Garner, Cafu; Knockaert, Krovinovic, Freeman; Grabban
We say: Birmingham City 1-0 Nottingham Forest
Birmingham look a completely different side under Bowyer, who could make a bit of history should the Blues win again at St Andrew's in midweek.
The hosts have gone four games without conceding, whereas Forest have fired successive blanks, so we are backing Bowyer's men to edge this Midlands derby.