If Liverpool want the first trophy of the Jurgen Klopp era soon they will have to play better than this. This League Cup semi-final leg at Southampton should have put them one step towards Wembley but they blew it, barely showing up and getting lucky that they were only beaten 1-0 by Southampton.

There is a second leg to play at Anfield on 25 January and Klopp’s team are still in with a puncher’s chance of making the final. But this was a huge failing, a dismal no-show, as they could not summon any of the intensity, speed or imagination that has made them such a threat in the Premier League this year.

Southampton have had an awful time recently, with three straight league defeats, un-enterprising football and fans starting to grow tired of Claude Puel. This was their first semi-final since 2003, and defeat might have turned the crowd against him. But Puel and the players rose to the occasion. Southampton looked far more motivated than Liverpool, and played with more energy and efficiency. They set about Liverpool on the break, turning Klopp’s gameplan back on his own team.

From the very start it was clear Liverpool could not cope with Saints’ surgical attacks. Nathan Redmond scored the only goal after 20 minutes but he could have scored a first-half hat-trick, and had another just before the end.

Dusan Tadic is brought down by James Milner (Getty)

It was Loris Karius, of all people, who kept Liverpool in the game. Defensive permeability is not a new problem for Liverpool but what is troubling is how poor they were going forward. They created almost nothing all match. Roberto Firmino forced an early but easy save from Fraser Forster and there was nothing else. All the usual speed and ruthlessness was gone.

It is a fair point to say that Liverpool did not have all of their best players available. Sadio Mane is at the African Cup of Nations, Jordan Henderson had a heel injury and Philippe Coutinho, out for seven weeks with an ankle injury, made his return with 30 minutes left of this game. Without those three Liverpool had no speed to their game, no invention, and were unusually easy to stop. Virgil van Dijk and Maya Yoshida played very well for Saints at centre-back but it should not have been as simple as this.

With no Henderson, Liverpool had Lucas Leiva and Emre Can in the middle of midfield. They were trundlingly slow in a way that Klopp teams are never meant to be. They were slow getting forward and, somehow, vulnerable to the counter-attack, truly the worst of both worlds.

Forster and his team defend a Liverpool corner (Getty)

This non-performance raises serious questions about Liverpool’s trip to Old Trafford to face a resurgent Manchester United on Sunday. Earlier on the season that would look like an easy Liverpool win but if they play anything like this then Jose Mourinho’s team will be too strong for them. The kindest thing that can be said about this display was that the players were conserving energy for Sunday but the fact is that it was only Saints’ profligate finishing that stopped them from winning 4-0.

After Liverpool dominated the first 15 minutes, the rest of the game was all about Saints. They broke so well it should have been taken as a warning. Cedric Soares crossed from the right, Nathan Redmond found space at the far post and should have scored. Loris Karius reacted fast enough to keep it out.

One minute later, Saints had their lead, after another lightning break that left Liverpool dreadfully exposed as they tried to play an off-side trap. Dusan Tadic played a forward pass and Ragnar Klavan could not adjust his feet to clear it. The ball went through to Jay Rodriguez who teed up Redmond. This time he made no mistake and put Saints ahead.

Milner in action for Liverpool (Getty)

Just before the break Saints cut Liverpool open one more time. Ryan Bertrand found Dusan Tadic, who darted in a clever low cross. Again, Redmond picked it up, but from close range he could not beat Karius. He might have had a hat-trick, but only had one, and Saints were just 1-0 up at the break.

Liverpool marginally improved in the second half, especially when they threw on Coutinho, but never enough to make anything like a real chance. Redmond continued to terrorise them on the break. He put through Cedric, who shot into the side-netting when he should have crossed. Then, eight minutes from the end, Redmond got into the end of Shane Long’s cross, chipping Karius, only for Dejan Lovren to block it on the line.

Southampton, ultimately, should have won this game by four or five. There was no real siege, no real fight from Liverpool, and despite the score line it is the winners who left with as many regrets as the losers.

Southampton (4-2-3-1): Forster; Cedric, Yoshida, Van Dijk, Bertrand; Romeu, Clasie (Hojbjerg, 73); Redmond, Davis (Ward-Prowse, 81), Tadic Rodriguez (Long, 81)

Liverpool (4-3-3): Karius; Clyne, Lovren, Klavan, Milner; Wijnaldum (Coutinho, 61), Lucas, Can; Lallana, Sturridge, Firmino (Origi, 82)

MoM: Redmond