The Reds had been pretty ordinary up to now in the Premier League, where they sat fourth on 36 points, some 14 behind Arsenal.
Differing fortunes in the league and Europe for both sides
Though they also trailed the Gunners in the Champions League table - they were ninth before a ball had been kicked at the Stade Velodrome - their passage into the knockout stages was virtually assured if they could see out their final two games successfully.
Marseille are eight points adrift of Ligue 1 leaders, Lens, but are in third position behind Paris Saint-Germain, and are having a great season.
In the UCL, however, they'd dropped right off the pace, and their nine points only just kept them in the hunt for a playoff place.
Their much-maligned attacker, Mason Greenwood, has also continued to be something of a talisman for the club, letting his football rather than his personal life do the talking.
Szoboszlai has been the main man for Liverpool
In Europe, particularly, the North West giants had been indebted to Dominik Szoboszlai, whose three goals had gone some way to keeping Liverpool at the right end of the Champions League table, and in terms of current form, the Reds were unbeaten in 12 games in all competitions.
Les Phoceens had lost only one of their last five in normal time, whilst scoring an astonishing 22 goals in those games.
Indeed, among all the clubs from Europe's big five leagues this season, only Bayern Munich (3.6) and Barcelona (2.7) have averaged more goals per game across all competitions than Marseille (2.6 - 69 in their 27 matches prior to Wednesday's match).
Arne Slot made four changes from the side that faced Internazionale in Liverpool's last Champions League game, whilst Roberto De Zerbi decided on changing a full half-dozen players from Marseille's last UCL encounter, with Union Saint-Gilloise.
Salah level with club legend
Mohamed Salah, who has had his problems with the club, was making his 88th appearance in major European competition for Liverpool, moving level with Ian Callaghan, and meaning that only Jamie Carragher (130) and Steven Gerrard (111) are still ahead of him in this regard.
For a game that promised so much, it was remarkably without incident in the opening exchanges.
Liverpool briefly threatened without ever really looking like scoring, and Marseille didn't have a shot of any description until Amine Gouiri's on-target effort just before the half hour.
The Reds had failed to get any shots on target in the same time frame, representing the first time since playing Ajax in October 2022 that this has happened; however, were it not for the slenderest of offside decisions, Hugo Ekitite would've opened the scoring in the 23rd minute after a lightning-fast break and the coolest of finishes.
Marseille in control until genius move
Marseille had even hogged two-thirds of the possession, with Facundo Medina in particularly impressive passing form (98.6% completion).
Along with Pierre-Emile Hojbjerg (93.5%) and Timothy Weah (90%), the hosts were enjoying leading the Premier League champions a merry dance at times, though Marseille's inability to carve out anything approaching a goalbound effort would come back to haunt them in first-half injury time.
Awarded a free-kick just outside the box, Szoboszlai stepped up and promptly rolled the ball underneath an airborne wall and into the net.
Not only was it inventive and highlighted the need to have players lying down behind the wall, but it gave Liverpool an advantage that firmly put them in the box seat, given they'd won all three UCL games in 25/26 that they'd taken the lead in.
Greenwood's growing confidence
The Hungarian also became just the third Liverpool player to register a goal involvement in five consecutive UCL appearances after Gerrard (twice, Oct 2007 – Feb 2008 and Sep 2008 - Nov 2008) and Salah (6, Sep 2022 – Feb 2023).
Marseille came out in the second half with much more purpose, and three shots in three minutes almost brought them the equaliser.
Greenwood's nine touches in the Liverpool box - at least three more than his teammates - evidenced his growing confidence, though Ekitike's shot against the woodwork just before the hour rattled more than just the frame of the Marseille goal, and drew an incredible tirade from De Zerbi.
The visitors still afforded Marseille the freedom of the Velodrome, but appeared content to draw the French side in before hitting them on the break, where they always looked dangerous and often outnumbered the hosts' defence.
Frimpong foxes Rulli
A mix of profligacy on the Reds' part and superb defending from the likes of Amir Murillo (16 one-on-ones contested) and Leonardo Balerdi (10), kept Liverpool's attackers at bay, and the second goal, when it came, was all Jeremie Frimpong's own work.
Despite Medina's best efforts to knock the wing-back off the ball, Frimpong's strength and pace allowed him to round the defender and, whilst his cross was intended for a teammate, Geronimo Rulli's attempt to clear the ball inadvertently span into his own net.
The first goalkeeper to score an own goal against Liverpool in the Champions League isn't something the Argentine will want to be remembered for.
Gakpo seals it
Three late shots from Igor Paixao were all off target and summed up Marseille's evening. As did the normally reliable Pierre-Emerick Aubameyang, when he fired straight at Alisson despite having the whole goal to aim at.
Cody Gakpo's 92nd-minute third for Liverpool rubbed salt into Marseille's wounds, given it was only their third shot on target in the game.
The hosts will surely rue the fact that despite having more total shots (15 to Liverpool's 11 - the Reds' lowest in this season's competition), more shots on target (4 - 3), more possession (58.1% - 41.9%), significantly more passes (572 - 412), and the same accuracy in the opponents half as their visitors (83.8%), that they weren't able to make more of what was clearly a great opportunity.
On such fine margins does the difference between success and failure rest.
Catch up on the match with Flashscore.
