Jurgen Klopp hit out at Manchester United's tactics in their 0-0 draw at Anfield on Sunday.
The German complained about United's defensive approach to their top-of-the-table clash and said their set up was 'the worst thing you can face in the world'.
The Reds were unable to break down United's defence throughout the match and extend their run without a Premier League goal to three games.
Defenders Luke Shaw and Victor Lindelof were standout performers for Ole Gunnar Solskjaer's side, but Klopp was left unimpressed by the 'world class' United after the match.