Leeds now meet Preston in the first leg of the play-off semi-finals at Elland Road on Friday before the return game at Deepdale on Monday May 8.
North End were 2-0 winners yesterday at Deepdale, but Blackwell insists the result will have no bearing on the outcome of the play-off battle.
"Now knowing who we've got, all four teams can now focus on the game," said Blackwell.
"Training becomes a lot more specific so I'm pleased it's out of the way."
He added: "There were a lot of changes (yesterday) but it was for a purpose. I don't think Billy (Davies) or I will read too much into the result."