Fulham's unbeaten start to the season came to a halt at Craven Cottage on Saturday.
The Whites shot themselves in the foot, conceding two penalties and a first-half red card .
We look at five things we learnt from the hosts first defeat of the season.
Johansen starts, but doesn't last long
The new signing from Celtic must have made an immediate impression on Jokanovic, who named him in his starting lineup for the first time.
He took the place of club captain Scott Parker - no easy boots to fill by any means - and slotted in alongside Kevin McDonald.
It meant he could sit back and allow his midfield partner to move more forward.
Or, at least, he could until he was hauled off after half an hour to bring on Jozabed in a bid to find the breakthrough.
Slavisa won't rush new signings
The Fulham coach has so far been hesitant to throw in new signings straight into the side.
Jozabed is a perfect example of this, the Spaniard yet to play 90 minutes having signed earlier in August.
Ragnar Sigurdsson and Chris Martin started on the bench for the Birmingham match, while Lucas Piazon did not even make the match day squad.
It makes sense too, with the manager understandably reluctant to alter a successful side .
Poor passing proved Fulham's downfall
The Whites have made a strong start to the season but their lacklustre midfield play cost them during the first half.
On several occasions, McDonald himself played some woefully short passes, while a rogue pass saw Michael Madl see his marching orders.
The Whites defender picked up a second yellow card trying to beat Donaldson to the ball after a sloppy pass.
Button’s Jekyll and Hyde game
The Fulham goalkeeper endured a horrible game, but he wasn’t the only one to suffer such a performance .
The former Brentford man made a fantastic save to keep out Donaldson from the spot, but that’s as good as it got.
He twice got caught out in horribly indecisive moments, which fortunately didn’t result in goals.
But he wasn’t so lucky the third time around, when he lingered on the ball for too long, and started a passage of play which resulted in Birmingham’s second penalty, and the opening goal.
Robust Birmingham caused problems
Fulham’s first post-international break match was not one to be admired, as their fine unbeaten run came crashing to a halt..
Players were sloppy, two penalties were conceded, and Jokanovic was making tactical changes after just half an hour.
Their opponents sat back behind the ball well, as was predicted, but their lack of incision cost them when Madl was sent off in the first half and Birmingham took the lead four minutes into the second half.
It will leave Jokanovic scratching his head after a strong August, in which the hosts looked indomitable at times.