Sweden striker Johan Elmander scored twice as Bolton won 3-1 at Upton Park to leave West Ham without a point after two Premier League games.
The Hammers dominated the first half but found Jussi Jaaskelainen in fine form, the Bolton 'keeper gathering Carlton Cole's weak penalty kick after the striker had been shoved over by Gretar Steinsson.
The visitors took the lead shortly after half time when Hammers defender Matthew Upson headed into his own net after Elmander flicked on Jaaskelainen's long kick.
Upson took a kick to the nose from Kevin Davies in the process and had to be replaced by Winston Reid to complete a bad day for the England defender.
Bolton looked to have wrapped up the win in the 68th minute when Elmander powered in a header for only his ninth league goal since a 10 million pound ($15.5 million) move to Bolton in 2008.
But Mark Noble gave West Ham hope with a 79th-minute penalty to make it 2-1, following Gary Cahill's foul on Scott Parker.
Elmander ended the hosts' hopes of a comeback, though, his emphatic finish six minutes before full time securing a seventh consecutive win for Bolton over West Ham.
''I am a great believer in Elmander,'' Bolton manager Owen Coyle told the Press Association. ''He will take confidence from that today. He is a great lad and a very good player.''
The result leaves Avram Grant still looking for his first point as Hammers manager, and with games against Manchester United and Chelsea coming next.
''We have a very tough two games,'' Grant said. ''On the football side everything went well today. We played like a team at the top. I am very happy with the performance, I am very disappointed with the result. It was a strange game.''
Grant also was convinced that Bolton's first goal should have been disallowed for Davies' kick on Upson.
''There was a clear foul. He smashed his face,'' the Hammers manager said. ''The referee needs to be more awake.''
