Liverpool's victory over Real Madrid came after a victory over Aston Villa in the league and snapped a streak of six defeats in seven matches.
But, what had looked like a revival quickly took a downturn with back-to-back league defeats leading to more unanswered questions and even whispers of concern over Slot's future on Merseyside.
AdvertisementAdvertisementAdvertisementAnother chastening defeat will do nothing to silence those naysayers.
After Dominic Szoboszlai's equaliser, Liverpool looked brighter. They played with more urgency and created more chances, Cody Gakpo going close with a powerful header before teeing up Mohamed Salah with a fast pass across the box, but the Egyptian was pipped to the ball.
PSV's second goal stunned Anfield and, from there, the hosts struggled to find solutions.
It was another difficult night for Salah, evidenced when he picked up the ball on the right - just outside the area in prime shooting range - but instead blasted over the bar.
AdvertisementAdvertisementAdvertisementAlexander Isak also again failed to impress when he replaced Hugo Ekitike, who worryingly limped off after an hour, and the Swedish striker's stint on Merseyside continues to disappoint.
Defensively, it was a struggle at times and, as PSV continued to find openings, Liverpool just capitulated.
Left-back Milos Kerkez was the wrong side of his man for the second goal, while Ibrahima Konate missed the ball for Driouech's first.
That goal prompted droves of Liverpool fans to head for the exits, and their biggest concern now seems to be just how their side are going to turn this around.
There have been questions over line-ups, formations, heart and desire and whether Slot has what it takes to restore confidence to what was once a glorious winning machine and feared by all.
With his players booed off at the end of this dispiriting loss, Arne Slot will have to find the answers soon.