Jurgen Klopp blamed complacency for Liverpool blowing a three-goal lead in their 3-3 draw with Sevilla on Tuesday night.
The Reds looked certain to qualify for the round of 16 when they entered the half-time break up by three goals, courtesy of Sadio Mane and a brace from Roberto Firmino.
Eduardo Berizzo’s side were a completely different team after half-time. Wissam Ben Yedder scored six minutes into the half, before converting from the spot-kick on 61 minutes after former Sevilla man Alberto Moreno tripped him inside the box.
In a dramatic finish, Guido Pizarro poked home in the third minute of injury time to secure a point for the La Liga club.
Speaking after the draw, Klopp said: “The description is easy – two different halves.
“A fantastic first half of my team and in the second half we made the mistake that we didn’t carry on playing football. It’s normal that you try to control the game then, but a team like we are, we have to control the game with the ball – and we didn’t play football anymore.
“We became a little bit passive, they scored the first one and it was obvious the atmosphere changed immediately. It gave them a big boost.
“Until the second goal, we were reacting but after the second goal I think it was an open game again. We could have scored off counter-attacks, but we didn’t. We opened the door for them and didn’t close it anymore, so they could score in the last minute and that was the story of the game.”