Sam Allardyce reevaluated the task in front of him while blaming"fatigue" as the reason behind Palace's second-straight defeat on Tuesday, a 2-1 setback at home to fellow relegation battlers Swansea City.
The result means Allardyce has taken only one point from his first three fixtures since succeeding Alan Pardew as Palace manager, leaving them just one above the bottom three.
They were again as unconvincing as in Sunday's 2-0 defeat at Arsenal, and Allardyce admitted he made an error by not making enough changes two days later.
Asked the main reason for the defeat, the 62-year-old said: "Fatigue. Not having enough recovery time compared to Swansea.
"That performance in the first half just wasn't good enough. I have to take a bit of responsibility -- picking almost the same team was the wrong thing for me to do.
"[This is proving] a bigger challenge, after three games, than I expected."
Allardyce was also critical of referee Paul Tierney for not giving them a first-half penalty despite goalkeeper Lukasz Fabianski not appearing to make contact with Christian Benteke when the striker went down, and one in the second when he felt Angel Rangel had handled the ball.
"The referee blatantly allows the goalkeeper to stay on the pitch and doesn't give us a penalty, so the referee's to blame, but we can't control the referee," the manager said.
"Then we had another really poor decision on the handball [by Rangel] from the referee, in the box. It's been a very, very difficult night for us all."