Philippe Coutinho, captain for the day, led the way with a curling shot into the top corner after six minutes.
Seven minutes into the second period Firmino volley in Coutinho's free-kick at the far post.
Two goals in a minute ensued Trent Alexander-Arnold rifling in his first goal for the club on 65 minutes before Firmino struck again.
Alex Oxlade-Chamberlain added his first home goal in Liverpool colours on 82 minutes.
Jurgen Klopp's side move back a point above Spurs, while Swansea stay bottom on 13 points, five off safety.(ANI)