Defending Premier League champions Manchester City were shocked at Upton Park as they suffered a narrow 1-2 defeat at the hands of West Ham United.
Strikes from Morgan Amalfitano and Diafra Sakho proved enough as City were only able to net a late consolation through David Silva despite creating 21 chances in the game.
The game started with City getting an early chance through Sergio Aguero, who fired an effort from 20 yards after managing to get behind West Ham's defence. Although the shot looked like it was heading towards the bottom corner of the net, Adrian managed to push the ball out for a corner.
Despite City's dominance in the opening stages of the game, it was West Ham who broke the deadlock in the 21st minute through Morgan Amalfitano.
Some excellent play from Alex Song and Enner Valencia saw the latter make a powerful run into the the box, where he squared the ball towards Amalfitano, who found the nets with a close-range effort.
West Ham, who seem to have been invigorated by the first goal, nearly doubled their advantage towards the end of the first half, but James Collins failed to connect with a loss cross from Amalfitano following a set-piece situation.
After the break, City finally started attacking as Adrian was forced to make an excellent save at the hour mark by Aguero. Four minutes later, the Argentine was again in the thick of action as he struck the post from six yards following some excellent play from Yaya Toure and Jesus Navas.
Despite City's spell of dominance, with Toure also hitting the bar in the 73rd minute, it was West Ham who again scored through Sakho, who powered a header past Hart after connecting with Aaron Cresswell's deep cross in the 74th minute.
City were finally able to pull a goal back in the 77th minute through Silva, who curled a delightful effort past Adrian after getting past a couple of West Ham defenders.
The Citizens pressed on for an equaliser in the closing stages of the match, with Toure finding the side netting and Stevan Jovetic forcing another save from Adrian, but West Ham held on to secure all the three points.