Boss John Gregory accepted he was to blame for Crawley's 3-1 defeat at home to Bradford City.
Reds were level at 1-1 - Joe Walsh cancelling out James Hanson's opening goal - when Gregory took off Gwion Edwards and brought on Conor Henderson in midfield.
The move backfired as Bradford went on to win the game through goals by Billy Knott and Mason Bennett.
Gregory said: "We responded well to going behind so I think I have to take a lot of responsibility because I made some substitutions that didn't work.
"In the past three games I have made substitutions which have been the correct ones but tonight I didn't make the right decisions from the bench.
"We got to 1-1 and I felt we needed someone to put their foot on the ball. I messed up so I have got to take the blame for the outcome."