3. Better coordination and movement between the front three and the fullbacks
It is no secret that the bulk of Liverpool's chances come through counter-attacks and the ability of both their fullbacks to create opportunities down the wide flanks. The duo of Trent Alexander-Arnold and Andrew Robertson have been the best fullback pairing in the world since the start of last season, but both of them had an off night in Madrid which resulted in the drab display we saw.
Liverpool's front three of Sadio Mane, Roberto Firmino, and Mohamed Salah are adept at creating chances for themselves, but they looked isolated and out of ideas in the final third against a staunch Atletico defence which gave them no space. Simeone was smart and he also suffocated Alexander-Arnold and Robertson in the wide areas, which resulted in lots of inaccurate passes into the box which no attacker could make much of.
Klopp will need to figure out a way to give his fullback more space for them to create. At the same time, the front three need to switch positions and latch on to the perfect spaces themselves to give their teammates a bit of room to pass the ball, which either of Mane, Salah, or Firmino, can collect. Given Liverpool's pace, dribbling prowess and positioning skills, the fullback's ability to create one good chance combined with the skillset of the front three would be Klopp's ideal go-to movement for the club to score. If the fullbacks have an off-game or are stifled yet again, the team's chances of winning look bleak.