Liverpool boss Jurgen Klopp says he knows how to pull off a Champions League upset ahead of meeting Barcelona.

It was in 2014 when Borussia Dortmund lost 3-0 to Real Madrid in the first leg of a Champions League quarter-final at the Bernabeu.

Two first-half goals from Marco Reus had Dortmund on the brink of a stunning turnaround as they dominated the Spanish club.

They couldn't find a third, however, with Henrikh Mkhitaryan coming closest when he hit the post.

"You could make a video of this game and show it to the teams that lose a first leg 3-0," Klopp said at the time.

He hasn't showed his current team the video but it has come up in conversation as the Reds need to overturn a 3-0 first-leg scoreline against the current kings of Spain tonight.

“We lost 3-0 there but then at home we changed seven or eight positions and we won 2-0 and we should have won 5-0 without a shadow of a doubt," said Klopp.

“We were clearly the better side. But it was Madrid then and it's Barcelona now. It's a big difference.

“I don't want to talk too much, but I have told the players that story.

“It doesn't mean that it will happen again but it is enough for me to believe. That is what we do, not more."

The Reds need to overturn a 3-0 deficit against Barca to reach the final.