The 29-year-old believes that the Reds were better than the Red Devils at different stages of the game.
But, Alisson implied that Liverpool were off the pace for most of the night.
As quoted by Anfield Watch's Twitter account, he told Liverpoolfc.com the following: "It’s really difficult to come here and speak about a defeat. We believe that we played in a few moments in the game better than them.
"But in a game you have to do everything to win and to make better your performance - we couldn’t do that. We all agree that we must improve our performance. We have to be more consistent.
"We have to come back to the clean sheets again and we have to play better with the ball making better choices - we all agree on that. This is what we are going to chase for the next game."
Anfield Watch Verdict
Alisson is spot on with his assessment of the clash against Manchester United. There were times when Liverpool threatened. But, the Reds just didn't play well enough for long enough.
Liverpool really let themselves down last night. Manchester United lost 4-0 to Brentford away from home prior to facing the Reds.
So, it's not like Liverpool lost to a world-class team. The Reds have only accumulated two points from a possible nine this Premier League season.
Jurgen Klopp needs to find a way to inspire his team. What we are seeing right now just isn't good enough.
Hopefully we see Liverpool lift in the next couple of games.