Underestimating FC Porto would be Liverpool's 'biggest mistake'.

That is the belief of assistant coach Peter Krawietz, who demands a concentrated and respectful performance from the Reds in the first leg of their Champions League last-16 tie tonight.

"Our next opponents are FC Porto and a lot of people have said that on paper it looks like one of the better draws," he told the official Liverpool FC magazine.

"But without going into details, we can say that we know that it will be a tough tie because FC Porto is a very big club in Portugal.

"They are a really competitive side, unbelievably strong physically, really smart tactically, and of course they are very, very ambitious, particularly in the international competitions. So it won’t be easy for us.

"Maybe everybody else is expecting us to go through but the biggest mistake you can make as a responsible person in football – as a player or a coach – is to expect an easy game because that is the point where you have already lost before you start playing."

Porto's pedigree is obvious from their form this season.

Sergio Conceicao's side have lost only twice in 90 minutes in 36 matches, and progressed from a tricky Champions League group containing Turkish champions Besiktas, Bundesliga runners-up RB Leipzig and 2016-17 semi-finalists Monaco.

Krawietz acknowledges the quality of the opposition but feels Liverpool can triumph over the two legs if they produce their very best - particularly with the second match to be played at Anfield.

"We know it will be difficult but we also know that it is possible to get through if we perform at a real high level and that is what we will try to do," said the German.

"It is good to play there first and hopefully we can use the advantage of playing the first game away, if it is an advantage, to try and score one, two or three goals and not concede too many.

"Then we will have the opportunity in the second game to use our home game, our atmosphere, our Anfield magic, to go through to the next round. But there is a long, hard way to go first."