By Tom Blow Jamie Carragher took a sly dig at Manchester United during their Boxing Day game against Aston Villa… only for it to backfire. Carragher described Liverpool’s failure to beat the Red Devils earlier this month as “their worst result of the season”. The remark was made at half-time when Unai Emery’s side boasted a two-goal lead after John McGinn and Leander Dendoncker found the net. United were much better in the second half and equalised through Alejandro Garnacho’s brilliant brace. They completed their comeback late on when Rasmus Hojlund ended his 15-game wait for a Premier Leag…