"We're massively disappointed with how we played and it was certainly the worst performance since I've been at West Ham and we just never looked at any time as if we were in control".
After the break, West Ham crumbled further.
Three minutes in and Adrian was forced to save the older Ayew's header from a Sam Clucas corner.
Ki Sung-yueng, Mike van der Hoorn, Andy King and Jordan Ayew all got on the scoresheet for Swansea as they moved above West Ham on the ladder into 13th place.
"The fans travelled through the snow to get here and we let them down badly. In this moment we are just below it, but we are progressing".
"It was hard for West Ham to follow us".
Moyes later apologised to West Ham fans for the club's worst display since he took over last November. Out the ball came - dropping to the one white shirt in a position to tap home, as the markers around him slumped.
There will be no more 7.45pm kick-offs in the Champions League
There will be preliminary rounds in both the Champions League and Europa League prior to their respective first qualifying rounds. UEFA president Aleksander Ceferin said: "Fans see the VAR screen all the time but nobody knows how it works".
King, who was making his first start since joining on loan from Leicester, poked in a third which took Swansea above West Ham in the table. They were sluggish, unfortunate, beaten.
Swansea got off to the flawless start when they took the lead in the eighth minute; Ki picking the ball up on the edge of the area and pinging it into the bottom corner. Then came the injury to Reid that left the Hammers with a makeshift defence, four regular full-backs across the line.
The win lifts Swansea to 13th, with 30 points, above West Ham and Huddersfield Town on goal difference. I'm hurting as much as you.
The win meant Spurs' Argentine manager Mauricio Pochettino became the first non- European coach to win 100 Premier League games.
Well, those fans who did make the 460-mile round trip were left wishing they hadn't bothered, for Moyes's players did a no-show.
The Portuguese has transformed his side since taking over from Paul Clement, winning 17 points from nine league games in charge.
Swansea have scored 20 of their 21 Premier League penalties.
When Egyptian worldwide Salah gave Liverpool the lead after 40 minutes it was his 32nd goal of the season in all competitions and the seventh game in succession that he had found the net. I am giving all the credit to my players.