Swansea staged a stirring second-half fightback to secure victory thanks to strikes from Jordan Ayew and Fernando Llorente.
West Brom defender Jonny Evans opened the scoring at the Liberty Stadium with a 33rd-minute header before Ayew responded with a headed effort of his own with 18 minutes remaining.
Fernando Llorente struck with four minutes remaining as Paul Clement's side secured all three points late on.
More to follow...