#1 Center back
Liverpool were the only team in the league who despite leading 4-0 at half time had the potential to blow up their lead and be lucky enough to salvage a point in the end.
Courtesy of their shambolic defense, they were leaking goals at their opposition's will. The urgency to add a reliable option saw them shell out £75 million for Virjil Van Dijk in January.
The Dutchman added much steel to the back-line and improved Dejan Lovren's performances substantially. However the Croatian was still committing errors occasionally, which proved costly for the team.
That said, Klopp should be looking to add at least one center-back to his squad who is capable of making it into the first eleven week in and out.
Some options for him are in the form of Ben Gibson, Ben Mee, Stefan de Vrij or Jonathan Tah. If Klopp is willing to spend big on his defense again, he might look at the likes of Toby Alderweireld or Kalidou Koulibaly who are top class names at the moment.