Liverpool strengthened their hold on a Champions League place with victory over West Ham, while bottom club West Brom lost again to increase their relegation concerns.
Liverpool beat the Hammers 4-1 at Anfield to move up to second, five points clear of fifth-placed Tottenham, who play on Sunday.
The Baggies lost 2-1 to Huddersfield, leaving them with just one win from 14 games under Alan Pardew.
Swansea are back in the relegation zone after they lost at Brighton.
The Swans were unbeaten in their previous five games under Carlos Carvalhal but went down 4-1 at the Amex Stadium. They are 18th on goal difference, while West Brom are seven points adrift of safety.
Salah, who scored the second and set up the first in another Liverpool romp, was again magnificent as Jurgen Klopp’s freescorers marched above Manchester United into second place.
The winger continues to make a mockery of Jose Mourinho’s decision to jettison him out on loan before he was eventually turfed out of Chelsea for around £15m. Thirty one goals so far this season. Six in six. In freezing February, with plenty of football to be played, he has already matched Luis Suarez’s best-ever season tally for Liverpool. It is incredible stuff – but Klopp preferred to concentrate on the efforts of others.