Cooper did not play in Leeds’ 4-3 defeat at Anfield last weekend due to an injury, with Koch making his debut for Leeds alongside young defender Pascal Struijk.
The Leeds captain went straight back into the team against Fulham, but the central defensive partnership with Koch looked shaky as the Whites conceded three more goals despite the win.
The pair are still new to each other, but Bielsa does not feel the defensive mistakes are due to that fact.
The Leeds boss does not believe that the errors they committed will improve if they just play more together in the coming weeks and months.
The Argentine said in a press conference when asked whether Koch and Cooper will improve with more time together: “I don’t think it’s a question of time.
“If there were problems today it wasn’t due to co-ordination.
“The difficulties they had today will not improve if they play more games together.”
Cooper and Koch could be given another chance to impress by Bielsa next weekend when Leeds take on Sheffield United.