Jürgen Klopp's team appeared to have qualification for the knockout phase stitched up at half-time of their penultimate group game back in November, having carved out a three-goal lead in the first half an hour of their visit to Ramon Sanchez Pizjuan.
However, Wissam Ben Yedder's quickfire double after the break and an injury-time strike from Guido Pizarro helped the Spanish side claim an unlikely point and keep their hopes of leapfrogging the Reds alive.
Liverpool went on to seal their place in the next round with a 7-0 thrashing of Spartak Moscow on the next matchday, and they have gone from strength to strength in setting up a last-four meeting with AS Roma.