Liverpool's night unravelled in brutal fashion as the Dutch visitors repeatedly exposed their defensive frailties.
PSV stunned Anfield by taking the lead inside six minutes, Ivan Perisic converting from the spot after Virgil van Dijk conceded a penalty with a needless handball. Liverpool responded quickly through Dominik Szoboszlai, who tapped in after Cody Gakpo's shot was parried, and the hosts briefly seized momentum as Gakpo and van Dijk both went close to putting them ahead.
But the Dutch visitors regained control before the break when Guus Til finished a well-worked move, and Liverpool collapsed defensively in the second half. Substitute Couhaib Driouech pounced to make it 3–1 after Ricardo Pepi's effort was saved, then added a second in stoppage time to seal a comprehensive 4–1 win.
Slot stressed he continued to feel backing from the board despite Liverpool having now lost nine of their last twelve matches across the Premier League and Champions League, their poorest sequence since the 1953-54 season.
"I feel I am okay with my position," Slot said. "I've been feeling safe. I've got a lot of support from above. They have been helpful to me, but they don't phone me every single minute of the day to tell me they trust me. I feel the trust, but I haven't spoken to them after this game."
The mood around Anfield remained tense as PSV punished Liverpool's defensive frailties, leaving fans stunned by a decline few anticipated. Slot admitted the atmosphere was bleak inside the camp.
"The emotions are very negative," he said. "It is a shock for everyone, for the players, for the journalists, for me. It is very unexpected. But we have to face where we are and fight really hard."
Former captain Steven Gerrard warned the team were approaching crisis territory, even if he held back from using the word outright.
"Crisis is a very strong word for players who have delivered for this club and for a manager who has delivered for this club," Gerrard said. "But that performance against PSV was not good enough. There are no excuses. You can't deny this team are struggling massively.
"Confidence is at an all-time low and they keep conceding. Unless the manager can find answers and stability, it will continue."
Slot still sought small positives, praising the players' early response.
"I want to be positive about the reaction after we went 1-0 down," he said. "Until half time we played a good game. The players have so much quality that it cannot continue like this."
Liverpool could also travel to West Ham on Sunday without Hugo Ekitike, who went off early in the second half with a back problem.