LONDON — Big-spending West Ham slumped to its fourth straight defeat to open the English Premier League after conceding an injury-time goal to lose at home to Wolverhampton Wanderers 1-0 on Saturday.

Adama Traore, Wolves' record signing this offseason, finished off a counterattack in the third minute of stoppage time to earn the promoted team a first top-flight win since 2012 and plunge West Ham into more trouble.

Preseason optimism at West Ham, generated by hiring Premier League-winning manager Manuel Pellegrini and spending more than $100 million on new players, has evaporated with the team making the joint-worst start to a season in its history.

West Ham also opened the 2010-11 season with four straight losses, and went on to be relegated.