Liverpool manager Jürgen Klopp admitted his side were fortunate to come away with just a 1-0 deficit after their EFL Cup semi final first-leg with Southampton on Wednesday night, but vowed that the second leg will be different.

The Reds produced a feeble display at St Mary's Stadium, several saves from goalkeeper Loris Karius and the aid of the crossbar ensuring Klopp's men are still in the tie for the reverse meeting in a fortnight.

Nevertheless, winger Nathan Redmond's first-half strike gave them a slender advantage to take to Anfield later this month and Klopp admitted his side were so below-par on the south coast that even Saints boss Claude Puel would be disappointed with the result.

Reds boss: We'll strike back in the second leg

He told journalists that their "start was really good" and that if they had "played like this for 90 minutes then it would have been very difficult for Southampton to cope with it."

But the German acknowledged that after they "conceded one goal" then "the game changed" and said: "Even if I would try to explain it, it's not easy because I'm not actually used to a reaction like this from my boys."

Klopp insisted that they "have to accept" the result and that their performance was "not good" although they were "again dominant [in the] second-half."

He declared that their deficit, and the manner of his side's performance, is "not a big problem" and that they "had to defend then with passion."

Klopp felt his squad did so, but lamented the fact they "had not a lot of chances" and noted only Roberto Firmino's effort in the first-half which was comfortably saved by Fraser Forster.

"We had a lot of moments in and around the box where we could have had a chance but we didn't make anything of it and that was the situation," he continued.

He insisted that in the aftermath of the result, their performance "doesn't feel good" but said that it's "still open" for the final.

Klopp even felt that both managers would be "disappointed" afterwards, insisting Saints boss Puel would be because "they only won 1-0 and have to go to Anfield afterwards."

The manager vowed that his side "will strike back" and "will be a different team" in the second leg, adding: "Everything will be different at Anfield. So, for us, it's still possible to go to Wembley and that's the target."

Asked whether Southampton's failure to score more goals came as a crumb of comfort to Klopp, he said that it is "the only comfort" and that it was "the third best result" if "you don't win [or] you don't draw."

"I don't like it too much but it's still possible," he added. "This team always shows a reaction and we have to show a reaction in this cup against Southampton.

"But it would be cool if we could already show a reaction at the weekend because we probably need a better performance to get something at Old Trafford."

Coutinho's return the highlight of the night, says Klopp

Yet despite the disappointment of the evening at Southampton, Liverpool welcomed back playmaker Philippe Coutinho after seven weeks out injured and Karius was in inspired form to deny the Saints a greater margin of victory.

"It was nice. The best news from tonight," said the Reds boss on the Brazilian's first run-out since November 26, stating that everyone "could see immediately how important he is."

Klopp said that Coutinho is "not at 100 per-cent" but said it was "important for him to have half-an-hour" which is "really important" as he "did well" and his return is "good."

On Karius, the manager said that the German performed well and that he "kept us in the game" because the second leg would be "much more difficult" if they had lost "3-0 or 4-0."

Klopp insisted that keeping the opposition out is Karius' "job" but said he was "not too surprised" by his performance, yet acknowledged that the 'keeper having "to make saves like this" suggested "something else is wrong in the game" which he said "was our problem tonight."

Klopp: Tactical note wasn't because we were frustrated

One memorable moment of a largely forgettable evening for Liverpool was striker Daniel Sturridge was seen reading from a note handed to him by Klopp with tactical instructions on in the second-half.

The England international initially appeared confused before passing on the note to teammates Adam Lallana and Emre Can as he looked to pass on Klopp's adjustments.

On what the note said, Klopp revealed that it was about a "new system" which he said was 3-5-2 with "wingers and two strikers and Lallana and Coutinho in the half-space."

He refused to divulge any more information on what was written but admitted he was "a little bit too late" in passing them the note because it was "when the game was running again."

He added: "That was our mistake. Seven or eight of the players knew immediately. Roberto [Firmino] needed a bit longer but he was close enough to us. That’s all. It wasn't because we were frustrated.”