Man City boss Pep Guardiola said: "I'm delighted. Congratulations to the team, we beat the champions with the quality they have.
"I saw in the guard of honour how incredibly focused they were, how they shouted. I saw their faces, that's why they're champions.
"They didn't come here to celebrate. They'd drunk enough beers and they came here to compete.
"So the chances we created, to beat them 4-0, it was so important for preparing against Arsenal and Real Madrid."
Liverpool boss Jurgen Klopp told Sky Sports: "Is the game important to us? I saw a brilliant attitude.
"They were quicker than us in mind. We lacked fluidity. Against Man City you have massive problems. We had moments. We had chances, we didn't use them. The result we have to take.
"If you want to lead this story in direction we were not focused, then do it. I liked my team's attitude. Isn't it nice another team can be champions when Man City can play so well?
"Man City are incredible. I saw their season, they didn't play a bad game."