There was only pride to fight for on both fronts heading into the final day, with Southampton already resigned to finishing bottom of the table, and Liverpool forced to settle for a fifth-placed finish.
The two sides duly played out a classic end-of-season contest which saw goals galore and sloppy defending at both ends, eventually ending all square at 4-4.
Any hopes that it would be a sunny walk in the park on the final day were quickly extinguished, though, and goals from James Ward-Prowse and Kamaldeen Sulemana saw them level things back up before the half-hour mark.
Sulemana then scored a stunning solo effort early in the second half to complete the turnaround, before Adam Armstrong made things even better for the hosts with a fourth.
However, the rollercoaster was not yet over and Liverpool scored twice in as many minutes to drag themselves back level again, with Cody Gakpo and Jota ultimately earning a point for Jurgen Klopp‘s men.
The tone was set early on for the topsy-turvy spectacular which followed, with Liverpool being gifted the lead after only 10 minutes.
A scuffed pass from Romeo Lavia inside his own penalty area laid the ball on a plate for Jota, who was in no mood to turn down such a present and duly converted the opening goal of the game.
Four minutes later, it looked as though Southampton were going to bid farewell to the Premier League with a whimper as Firmino marked the final game of his legendary Liverpool career by getting on the scoresheet in trademark fashion.