Tomas Soucek, who put the ball into his own net at Tottenham last week, bundled the ball in over the body of Michail Antonio, but while the ball did not touch the West Ham striker, he was deemed to be blocking the line of sight of Kepa Arrizabalaga while in an offside position.
Even then, West Ham scrambled back on level terms before the break,
Antonio Rudiger summed up the off night Chelsea were having when he needlessly sliced the ball over his own line for a corner in first half injury time.
This time, Jarrod Bowen picked out Soucek directly and his downward header evaded Abraham’s best efforts on the line.
Chelsea’s appalling defending continued into the second half and Antonio was unmarked in the perfect place to put West Ham in front again minutes after the break.
Moyes was drawing on all the experience he had to get West Ham over the line, sending on Jack Wilshere for his first appearance since October.