Speaking after Liverpool's 3-3 draw against Benfica at Anfield, as cited by Anfield Watch's Twitter account, Klopp said that he expects a couple of really difficult games against Villarreal.
"I obviously saw the results and the game last night, it was very impressive I have to say. To kick out Juventus and Bayern Munich, you deserve to be in the semi-final. Give me time to prepare for it and we'll be ready.
"It'll be tough. We haven't analysed them but they have real quality. They have the most successful cup competition manager in world football, he knows what he is doing.
"It will be a tough cookie but we are a tough cookie, so who cares? We expect a couple of really difficult games."
📺 Jurgen Klopp on facing Villarreal:
"Tough, tough, tough, tough. Villarreal has probably the most successful cup-competition manager in world football, so he knows what he is doing. And the team is really strong." 🔴 pic.twitter.com/yxvAMnnXFB
Klopp was also asked if he was 'disappointed' that Villarreal knocked out Bayern Munich, as cited by Anfield Watch's Twitter account.
"I never realised I had the chance to make a choice! It was clear one of the two would be our opponents, but Villarreal deserved it."
Anfield Watch Verdict
The Villarreal game is by no means a done deal. Unai Emery's side were huge underdogs against Juventus and Bayern Munich yet they're now in the semi-finals.
Emery will set his side up very well defensively and it's going to be a big task for our forward line to break it.
The Yellow Submarine also have a lot of threats going forward. Arnaut Danjuma, who has six goals this Champions League campaign, Samuel Chukwueze and Gerard Moreno will all cause Liverpool trouble in the final third.
However, even though Klopp won't admit it, the Reds are huge favourites to advance to the final of this season's UCL but we can't underestimate Villarreal. Bayern and Juventus did and they've been knocked out by the Spanish side.