Nathan Redmond capitalised on another Ragnar Klavan error to send the Saints halfway towards the EFL Cup final with a 1-0 first leg win.
With Manchester United beating their underdog opponents Hull City on Tuesday night, Liverpool had the chance to copy their rivals by pulling off a win over Southampton in a game where the Reds were the favourites.
Liverpool were off to the better start, dominating possession, but struggled to break down a very defensive Southampton side.
Against the run of play though, Klavan was back at it again, making another clumsy error which gifted Redmond with his second one-on-one in just as many minutes - and this time he tucked it away.
Despite seeing most of the ball after this, Jurgen Klopp's side offered very little as they meandered towards half-time. Adam Lallana and Dejan Lovren continued to endure jibes from the fans of their former club, more so than Nathaniel Clyne, and were doing very little to shut them up as both players put in below par performances - much like everyone else in fluorescent green.
Claude Puel's side actually looked more likely to score, despite hardly having the ball, and produced yet another opportunity for Redmond who was denied by a brilliant save from Loris Karius.
Liverpool have gone in behind at half-time for the just the 4th time in 26 games across all competitions this season. pic.twitter.com/LSQBisoKrO— Squawka Football (@Squawka) January 11, 2017
No changes in terms of personnel for Liverpool at half-time and no change in terms of performance either as the Reds kept up their lethargic, lacklustre performance.
As time went on, Klopp's side gradually began to pick up the pace and tested Fraser Forster with a few long-range efforts - a task that the 6ft 7in keeper was up to.
With half an hour to go, the returning Philippe Coutinho was thrown on in place of Gini Wijnaldum - who was probably the best of the midfield trio fielded by the German - in an effort to salvage something from the game.
The introduction of Coutinho looked to have added a spark to the Anfield outfit but, much like the goal, the superior possession only ended with a goalscoring opportunity for the Saints, this time for right back Cedric Soares who blasted the ball wide.
Redmond again came close to scoring his first ever brace when Lucas slipped, allowing substitute Shane Long to slip the ball through to the winger, but his effort clipped off the bar before being cleared by Lovren.
The two will meet again for the second leg two weeks from now on January 25th and will need to do a lot more than they did today if they are to beat Southampton to the final.