With 12 first-team players not making the trip to Eindhoven, Liverpool’s group of young and fringe players were gifted the lead midway through the first half.
Joey Veerman’s touch in his own box allowed Federico Chiesa to toe the ball away, and the PSV midfielder's rash challenge meant Cody Gakpo opened the scoring when he stroked home from the penalty spot against his former team.
It proved to be the opening act of a frantic 25 minutes, with the home side striking back nine minutes later, as Johan Bakayoko’s excellent dummy saw him evade two Liverpool defenders and smash home an equaliser.
Peter Bosz’s side were only level for five minutes as Walter Benitez denied Chiesa, but Harvey Elliott pounced on the rebound to put the English side back in front.
However, the Boeren would stun the league phase leaders with two goals in five minutes on the stroke of HT.
First, Ismael Saibari smashed his team’s second equaliser into the roof of the net from a tight angle, before Ricardo Pepi got the faintest of touches to a deflected cross to complete an unlikely first-half turnaround.
With both teams’ fate all but secured, as Liverpool were guaranteed a top-eight spot and only an unthinkable sequence of results would see PSV miss out on the play-offs, the second half was a tame affair on the pitch, although that did not dampen a brooding and joyous atmosphere in the stands.
The best chance of a quiet second period fell to Saibari, who took a split-second too long to get his shot away when through on goal, allowing Tyler Morton to deny him with a last-ditch tackle.
In the dying minutes of the game, Liverpool’s disappointing night was complete, as Amara Nallo was shown a red card just minutes after entering the field to make his full debut, as he fouled Bakayoko as he was running through on goal.
Despite failing to make it a perfect eight wins from eight matches, Liverpool finished the league phase in top spot, as Barcelona failed to leapfrog the Reds as they only managed a draw against Atalanta at the Camp Nou.
Not only is this a huge confidence boost, but the win helped PSV climb to 14th in the table and comfortably take their place in Friday’s play-off draw.