Birmingham are fully aware that they need to come to terms with life in the Premiership as quickly as possible but they have not helped themselves with defensive lapses.
They have repeatedly been warned by manager Steve Bruce, but yet again they fell to the early goal when Yorke opened his Blackburn account.
Yorke, back in partnership with his old Manchester United colleague, had a somewhat mixed match. He made an early impression but then faded.
But by that time he had scored the crucial opening goal in the 13th minute after David Dunn and Nils-Eric Johansson had combined to open up Birmingham's defence.
Dunn's shot was blocked but the livewire Yorke pounced to score with an accurate shot past Nico Vaesen.
Cole was prevented from grabbing a second goal for Blackburn by the combined efforts of Vaesen and Kenny Cunningham.
Blackburn's goal came under pressure with American Brad Freidel saving a powerful free-kick from Martin Grainger.
In the second half Birmingham strived unsuccessfully for the equaliser. They were twice denied by brilliant saves by Freidel to prevent goals from Darren Purse and Aliou Cisse.