The Argentina international served a mandatory one-match ban for his red card at Old Trafford and also admitted an FA charge of improper conduct.
Mascherano, 23, served the first instalment of his additional suspension at Arsenal on Saturday.
Liverpool were unhappy with the "inconsistency of sentencing based on past precedents", with Mascherano seen as a scapegoat for some recent high-profile displays of petulance towards referees.
Those precedents may have included the cases of Arsenal striker Emmanuel Adebayor, who staged a long protest after being sent off in last season's Carling Cup final, and that of Watford's John Eustace, who showed a reluctance to leave the field after being dismissed last month.
Both players received additional one-match suspensions, half the punishment meted out to Mascherano.
The midfielder challenged the sanction on the grounds his ban was excessive but this was dismissed on Thursday by an appeals panel.