Ahead of the La Liga outfit's arrival at Anfield, we take a look at the pressing issues ahead of the Group E opener.
"I wonder if the manager is sitting there this morning thinking, 'is my back-four good enough to go where I want to go with this team?'"
Defensively, though, Liverpool were weak in both legs against Hoffenheim; they could easily have conceded more than three goals in the tie. "I don't think it's what we deserved".
"I had a chat with Klopp and wanted to put right the initial mistake.
It was an exciting game from my side, everyone saw our desire and passion but we got a point", Klopp told BT Sport. The Colombian played in Joaquin Correa for a 72nd minute equaliser in a game which finished 2-2.
That missed penalty was the first in the Champions League for Liverpool in almost a decade, when club legend Steven Gerrard missed from the spot against Marseille in December 2007.
Dejan Lovren lunged at a cross he would have been expected to clear and Wissam Ben Yedder poked home.
"There is a lot from this game on which we can build and that's what we will try, of course".
'But playing against the better teams in the Champions League, and the Premier League, they're going to have to tighten up at the back. "It is disappointment, frustration, but that is completely normal", he added.
"We were just unlucky, Bobby [Firmino] hit the post and that can happen - you can't score every penalty, so it was just unlucky. That means you have to take it and use it, you have to feel disappointment".
Liverpool will most-likely start with Philippe Coutinho, as his failed move to Barcelona over the summer has landed him with the Reds. After a year without a single red card the reds have now collected two in two games.
"It helped him that he could play tonight in the long-term, that's for sure".