Christian Benteke scored the only goal as Liverpool ended 2015 with victory, leaving Sunderland in deep trouble.
Benteke netted early in the second half, running on to Adam Lallana's pass to neatly net from inside the area.
Vito Mannone made a stunning save to tip Liverpool midfielder Roberto Firmino's shot on to a post before pushing away the Brazilian's header.
Jermain Defoe forced Simon Mignolet into an excellent save, but Sunderland have now lost their past five games.
Fabio Borini also went close against his former side, shooting straight at Mignolet and striking an effort narrowly wide.