Liverpool boss Jurgen Klopp insists the Reds still have work to do to secure a spot in the Champions League final, and expects Villarreal to try "with all they have" in Tuesday's semi-final second leg.

The Reds are still chasing a historic quadruple after beating the Yellow Submarine 2-0 in last week's first leg at Anfield, with goals from Andrew Robertson and Sadio Mane putting Klopp's team on the brink of a third Champions League final during his seven-year tenure.

Klopp's team produced a dominant performance at Anfield to restrict Villarreal to no attempts on target and could become the first team since Porto in 2003-04 (against Deportivo La Coruna) to not concede a single shot on target across a two-legged Champions League semi-final.

Liverpool also recorded 22 high turnovers as they suffocated Unai Emery's team, the most by a team in a Champions League knockout game this season and the most Klopp's Reds have ever produced in the competition.

However, Klopp insisted his team would have to withstand a fierce Villarreal response on Tuesday, and said Liverpool would not take anything for granted.

"No [the tie is not over], we know that. It's half-time. In the best possible way, we ignore the result from the first game," Klopp told his pre-match press conference.

"As if it was a cup tie with only one leg and it would be decided in Villarreal, we will try to win there, that's what we want to try, knowing that they will go with all they have, that was clear with all the things Unai said after the game.

"It will be another tough one, but it's fine, the Champions League semi-final should be tough. We never expected it to be easy and this will not be easy. We played a good game at home, and we had better play a good game there as well.

"The Champions League semi-final is the second-most important game you can play [after the final]. That's why whatever happened in the last few weeks is not important.

"You never know if you will reach the semi-final again if you will ever have another chance to go to the final, you never know. We have an exceptional team here, but nothing is taken for granted, you better treat it carefully and be ready, and we will be ready."

Liverpool have won on all five of their Champions League road trips this season. Should Klopp's side win in Spain, they would have played the most away games while maintaining a 100 percent record by any team in a single European Cup/Champions League campaign.

With the Reds on a 13-match unbeaten streak on their travels in all competitions, Klopp highlighted the importance of having extra options available in his squad compared to previous seasons.

"In general, our last periods of the season are pretty intense, because the Premier League is so difficult," Klopp added.

"It helps that we know, historically we are in the best possible shape [physically], where we don't have to push the boys through like we did in 2018, where we arrived at the final [a 3-1 loss to Real Madrid] pretty much on three wheels, with players coming back from injury and these kinds of things.

"We have to make sure we can make changes here and there and keep them all in rhythm, and to win the football games, that's what it's about."

Tuesday will also see midfielder Thiago Alcantara return to Spain after an outstanding first-leg display in which he attempted over 100 passes, and Klopp said the in-form 31-year-old would start for any team in world football.

"When Thiago is in the shape he is in now, he would play in each team in the world, and he would perform for Spain as well," he added. "He had problems when he arrived here, he got injured, and Spain obviously has a lot of options in midfield because it's an incredibly talented football team.

"But in the shape, he's in at the moment he would play for each national team, and not only play in it, he would probably be the outstanding performer. 

"Every person needs to be fit and to gain rhythm and then he can show his best football. If he's in the right place physically, he will show everyone how good he is."