The Merseysiders were reduced to 10 men after just 13 minutes at Old Trafford, when Idrissa Gana Gueye was dismissed for violent conduct for slapping team-mate Michael Keane.
But United failed to make the most of our one-man advantage, and Kiernan Dewsbury-Hall's strike in the first half - following the red card - proved enough for David Moyes's team to take all three points away from M16.
United mounted plenty of pressure in search of a response but failed to find an equaliser, with Amorim disappointed by a lack of intensity from his team.
Watch the press conference in full, or read Ruben's quotes below.