West Ham withstood a barrage of second-half pressure to condemn Manchester City to their first defeat of the Premier League season.
Goals from Victor Moses and Diafra Sakho got the Hammers off to a flying start at the Etihad Stadium and they held on for a 2-1 win after Kevin de Bruyne pulled one back.
City dominated after the break and created a series of chances but Hammers goalkeeper Adrian was in outstanding form and refused to be beaten.
It was another notable away victory for Slaven Bilic’s West Ham after securing wins at Arsenal and Liverpool already this season.
City won their first five Premier League games of the season — and a club record 11 in succession — but, coming after a Champions League loss in midweek, they made a sluggish start.