BARCELONA (AFP) - Jurgen Klopp has insisted Liverpool are ready to end Lionel Messi's Champions League mission by beating Barcelona in the semi-finals.

Messi has been rested for Barca's last two league games and appears more motivated than ever in Europe, after pledging to "bring that beautiful cup back to Nou Camp " at the start of the season.

But Klopp has warned his players not to focus only on the Argentinian.

"It's not only about Messi but of course it's about him as well," Klopp said at a press conference on Tuesday (April 30).

"Can we concentrate on Messi? We should in a lot of moments but if we only concentrate on him, there are 10 other world-class players who can decide the game as well.

"Messi said before the season, 'we want to bring back that cup'. That sounds like a threat to me. Now we did it, now we are here and all I can say is we want to go to the final as well."

Barcelona play Liverpool in the first leg on Wednesday, four days after celebrating winning the Spanish LaLiga on Saturday. With a Spanish King's Cup final this month against Valencia to come, it means a treble is in their sights.

Barca midfielder Ivan Rakitic said: "Leo has been a LaLiga champion 10 times in 15 years and of course, after seeing him lift the cup (on Saturday) with such happiness, that motivates everyone.

"If Leo is happy to win every title, it makes us even more eager too. We know we're Barca, we have to give everything and following the best player in history gives us more confidence to do that."

Liverpool hope to have their own striker back in time for the first leg, after Roberto Firmino trained after recovering from a muscle strain.

"If he is 100 per cent ready to play he will maybe play," Klopp said. "He is here. Tomorrow we have another session."

Messi is likely to be flanked by two former Liverpool players, with Luis Suarez and Philippe Coutinho expected to start in an attacking three.

But while Suarez has flourished in Spain, Coutinho has struggled to find his feet since joining Barca for €120 million (S$183 million) in January last year.

"We miss Phil Coutinho a lot because he is a world-class player and I loved working with him," Klopp said. "When I first heard he wanted to go to Barcelona I couldn't imagine it would be good. But we had to deal without him and we did well."

Barcelona have not lost at home in the Champions League since 2013 while the last English opponents to beat them on their own turf was Liverpool in 2007.

"A draw would not be the worst result in the world, not that we would go for it but it would be okay," Klopp said.

"It would mean a lot to win. It's difficult, so many teams came here with an idea to do this or that and they got a big knock. But we saw the game against Real Sociedad and they did well. Levante did well a couple of days ago. But the better the opposition is, the higher the stakes are, and the more they are engaged.

"Now they are champions, they can completely focus on the Champions League."

Liverpool have lost only once in the Premier League this term and are still fighting with Manchester City to win the title.

Mohamed Salah, Sadio Mane and Roberto Firmino already boast 68 goals this season between them.

"We need to stop them running at our defence," Rakitic said. "We are going to try to score but we mustn't lose our heads."

"We know in these ties one good game is not enough, you need to play two great games," coach Ernesto Valverde said. "If you switch off for five minutes against Liverpool, they can finish you off."