Jurgen Klopp understands Manchester City boss Pep Guardiola's claim Liverpool are the toughest side he has faced during his managerial career.
Guardiola tussled with Real Madrid and Atletico Madrid during his time in charge at Barcelona and then crossed swords with Klopp's Borussia Dortmund while in the Bayern Munich hotseat.
The City boss, though, called the Reds "the toughest opponent" he has ever faced when speaking after his team's 4-1 humiliation of neighbours United on Sunday.