LONDON • Liverpool face an uphill task to qualify for their second straight Champions League final but, even at 3-0 down, manager Jurgen Klopp believes the tie is not lost yet as "we have another game and our people will be there".

Barcelona captain Lionel Messi orchestrated the Reds' heaviest defeat of the season with two goals, his second a stunning free kick into the top corner to bring up a staggering 600 goals for the club, 14 years to the day since his debut goal.

While Klopp conceded that "in these moments, he is unstoppable", the manager took heart from his team's Nou Camp display - declaring he "did not know if we can play it much better" and claimed he "was happy in how we defended the whole Barcelona team".

He said: "I am a big admirer of them, as is everybody, but my boys didn't show too much respect. We played football and I liked that.

"Football is like this. It is about scoring goals and they scored three and we scored none. The boys played a super game, to be honest but, against a side like Barcelona, a few moments are enough to give them the opportunity.

"It was the best Champions League game we played, not only this year, but last year as well - how we defended, how brave we were in these situations, how we were when we got the ball.

"We were not always brilliant, but we controlled the game in moments and created. Maybe not constantly (creating) chances, but we had moments."

James Milner and Sadio Mane had shots saved while Mohamed Salah struck the post to give Klopp hope, with Roma last season and Deportivo La Coruna in 2004 the only teams to have overcome a three-goal deficit to advance in Europe's top club competition.

The German said: "Because it is football, (so) we should still try."

His players were also on the same page despite suffering a blow yesterday after local daily Liverpool Echo revealed that Naby Keita, who went off early in the first half and would miss the rest of the season after suffering a small tear in a groin muscle.

Virgil van Dijk, the Professional Footballers' Association Player of the Year, told the club website: "There's a big job to do over at Anfield. We have shown throughout the season we never give up, so we have to just believe."

Fellow defender Andy Robertson also insisted his teammates will continue to "fight for everything".

The Reds' belief that they can conjure up a comeback next Tuesday, which would surely rival the 2005 "Miracle of Istanbul", has also put Ernesto Valverde on notice.

The Barca coach pointed to their shock quarter-final exit last term at Roma despite a 4-1 cushion from the first leg and insisted he would be taking nothing for granted.

He said: "The tie is still open and we haven't got through yet.

"They were better than us for some spells and we know what awaits us over there. I see a team that has the ability to make any team suffer."

As it was, it took a wonderful pass from Jordi Alba, turned in adroitly by former Liverpool favourite Luis Suarez just before the half-hour, to undo the visitors who combined disciplined defending, dogged midfield play and intelligent, energetic pressing.

Midfielder Arturo Vidal admitted: "Things will be much harder over at their place than tonight."

AGENCE FRANCE-PRESSE, REUTERS, THE GUARDIAN