A superb no-look pass from Lauren James set up Aggie Beever-Jones, who swept home to give the visitors a second-minute lead. Far from rolling over, however, the Hammers grew into the game and looked to have equalised through Honoka Hayashi, only for officials to incorrectly rule she was offside. The lively Riko Ueki nearly scored a goal of the season contender when her 30-yard strike crashed off the crossbar, before Viviane Asseyi missed a glorious chance from four yards out as the fortunate Blues limped into the interval with a slender advantage.
Ueki was the next to be hit with more bad luck as the Japanese international rounded Hannah Hampton in goal, but was wrongly flagged for offside early in the second half. Chelsea managed to weather the storm and after some second-half changes, substitute Erin Cuthbert put the game beyond doubt with a delightful finish two minutes from time to secure a crucial three points.