Andre Ayew opened his West Ham account by scoring against his former club as they piled further pressure on Swansea City manager Bob Bradley with a 4-1 Premier League win at the Liberty Stadium.
Ayew, who traded south Wales for east London in August, had failed to find the net in 10 games for West Ham going into Monday's meeting.
But he ended his wait at his old stomping ground on Boxing Day, a simple close-range finish after Lukasz Fabianski had inexplicably parried an Andy Carroll header into his path giving West Ham a 13th-minute lead.
West Ham were in control throughout the first half and five minutes into the second period they made it 2-0 as Winston Reid headed home at the near post from a corner.
The visitors were content to play on the counter-attack and preserve their two-goal advantage and, though West Ham goalkeeper Darren Randolph pulled off a string of fine saves, Swansea could not prevent a seventh defeat in 11 games since Bradley took over in October.
Gloss was added to the scoreline when Michail Antonio diverted Havard Nordtveit's drive beyond Fabianski before Fernando Llorente and Carroll traded late goals.
West Ham are now eight points clear of the bottom three, Swansea remain four adrift of safety in second bottom.
It took 10 minutes for Swansea to craft the first opportunity of the contest, Borja Baston curling well wide of the goal after good work from Jack Cork.
Perhaps jolted into life by that escape, West Ham immediately responded and broke the deadlock courtesy of a helping hand from Fabianski.
Mark Noble found Carroll with a high diagonal ball and, although Cheikhou Kouyate could not connect with his downward header, Fabianski palmed it straight to Ayew to tap in and break his West Ham duck.
Antonio could have made it 2-0 had he got on the end of an Ayew flick-on - though he appeared to have been offside - and Dimitri Payet tested Fabianski with a well-hit low drive.
Randolph was finally tested in the 41st minute, diving low to his left to turn a Gylfi Sigurdsson free-kick behind, before Cork looped a header over in first-half stoppage time.
Swansea's task was made even harder after the restart as they paid the price for more sloppy defending, Reid escaping his market and outmuscling two defenders to nod Payet's delivery into the bottom-left corner.
Cork drew Randolph into another diving save with a powerful long-range effort, and the shot-stopper showcased more quick reflexes to keep out Wayne Routledge's point-blank header.
Sigurdsson was similarly frustrated by Randolph after he had been teed up by Llorente, but any hope of a comeback was extinguished when Antonio turned in from close range after Edimilson Fernandes had been initially denied by Fabianski.
Llorente smartly turned home from Nathan Dyer's pull back to give Swansea something to cheer about, but Carroll immediately responded by emphatically lashing in Sofiane Feghouli's cross.