It was the perfect afternoon for the Millers, as they moved out of the relegation zone, with goals from Matt Derbyshire and Tony Andreu.
Here is a numerical analysis of the game.
-6 - The number that the Millers' goal difference now stands on after the success, no longer the worst in the division.
0 - The number of changes that Millers boss Steve Evans made to his side, just the second time this season he has kept an unchanged starting XI.
1 - The number of away wins the Millers have now registered after opening their account in the Second City.
2 - The number of clean sheets the Millers have chalked up this season in the league, the first in six games, the first on the road and the first with this current back five of Lee Camp, Lewis Buxton, Farrend Rawson, Danny Collins and Joe Mattock.
4 - The number of key passes made by Jonson Clarke-Harris, who although did not score still made a positive contribution.
5 - The number of goals the Millers have scored during minutes 60-65, Andreu's effort adding to the tally, their most prolific period, in games this season.
7 - The number of away goals the Millers have scored so far this season, already almost half of the 15 they managed in the entire campaign last year.
7 - The number of points the Millers have accrued in their last four games, since Evans branded it the 'start of their season' ahead of the clash at Charlton.
7 - The number of games since Jordan Bowery was last named in a matchday squad as the one-time record buy's time at the Millers looks to be hanging by a thread.
9 - The number of different people who have scored for the Millers this season after Andreu added himself to the list.
12 - The number of years since the Millers last won back-to-back games in the second tier, going all the way back to 2003 when they followed up victory at Bradford with a Boxing Day success at Wigan.
18 - The number of shots the Millers fired in at Birmingham's goal during the 90 minutes, with nine hitting the target and nine going off target.
21 - The number of games since the Millers last won by a two-goal margin, coming in their previous away win - a 2-0 success at Huddersfield in March.
26 - The number of years since the Millers last beat Birmingham, going back to Bobby Williamson's hat-trick inspired 5-1 win in 1989.
44 - The number of passes Norwich loanee Vadis Odjidja-Ofoe made during the match, the most prolific in the Millers outfit.
49 - The number of years since the Millers last won at Birmingham, a 3-2 success just two months after England won the 1966 World Cup.
50 - The number of days the Millers have spent in the relegation zone this season after they finally climbed out following this win.
61 - The number of games since the Millers last registered two victories in a row, going back to a 4-3 success at Gillingham in April 2014.
119 - The number of minutes in total the Millers have been leading in games this season as they added 58 to the total at St Andrew's.
204 - The number of days since the Millers' last away win against Huddersfield.
1013 - The number of minutes between Derbyshire's goal on the opening day of the season against MK Dons and his effort against his former club.
