Javi Gracia admitted Leeds were “very bad, “soft” and lacking “aggression” as they conceded five at home in the top flight for the first time in 32 years.
The Leeds coach saw his side throw away a first half lead from Patrick Bamford, to leak five in 32 minutes including two from Crystal Palace forward Jordan Ayew.
It was their joint heaviest defeat at Elland Road and Gracia said: “I cannot explain it after a good first half. We have to be really disappointed because the second half was very bad, the result as well is difficult to accept.