Ajax coach Marco van Basten has launched a scathing attack on his players following the "humiliating" defeat to Heerenveen.
The Amsterdam club were 2-0 down after just eight minutes before eventually succumbing 5-2 in heavy rain at Abe Lenstra Stadion.
To add insult to injury, Gregory van Der Wiel was sent off in the closing minutes for Ajax and Van Basten was unable to hide his anger at the performance.
"It is unbelievable you can let yourself be slaughtered like they did against Heerenveen," said the former Holland coach. "I had the idea they were playing for the first time in the rain. You get the feeling they are fair-weather players.
"It was a drama, totally incomprehensible. I've never been part of such a slaughter party before. Humiliating. This is a totally new experience for me. I don't understand a bit of it how you can let yourself be humiliated like they did, as Ajax players.
"I hadn't even sat on my chair and we were already 2-0 behind. After that you barely saw a reaction from the team. They were looking at each other and doing nothing to help one another.
"For me it's confirmation these players are not educated in mental defence. We need a new mentality and quality."
• Ajax have agreed a short-term deal with veteran goalkeeper Hans Vonk because of the injuries to Maarten Stekelenburg and Dennis Gentenaar.
The 38-year-old South African will stay at the Amsterdam ArenA until the winter break, with stoppers Stekelenburg (shoulder) and Gentenaar (hernia) both expected to be out for six weeks.
Vonk, who had been without a club since leaving Ajax Cape Town earlier this year and has not played since May, told De Telegraaf: "It's very nice, a great way to make a comeback.
"I was surprised when they contacted me, but I immediately had a good feeling."
Vonk played for the Amsterdammers between 2004 and 2006, playing 27 Eredivisie matches.
In the coming months he will likely act as back-up for Kenneth Vermeer until either Stekelenburg or Gentenaar returns.
He added: "I had planned to keep myself fit until the winter break and then decide what to do. There were offers from Johannesburg, but it was not an option for our family to leave Cape Town."