A "baffled" West Ham boss Sam Allardyce says the decision to disallow an early Alex Song goal was "complete nonsense" as his side lost a second straight Premier League match.

The Barcelona loanee had a volley ruled out, after Diafra Sakho was flagged for offside, before the Hammers went on to lose to Arsenal 2-1.

"The officials clearly got it horribly wrong," said Allardyce.

"Frustrated is an understatement. Baffled is more the feeling."

Song's 20-yard volley flew through the legs of Sakho and in to the net early on, only for the Hammers striker to be penalised for offside, before Arsenal went ahead on 41 minutes through a penalty from Santi Cazorla.

Danny Welbeck doubled the visitors lead and, despite Cheikhou Kouyate pulling a goal back after the break, Allardyce was left furious at referee Neil Swarbrick's early decision.

"They said the attacker was in the eyeline of the goalkeeper," said Allardyce. "Complete nonsense. It is impossible for the assistant referee to say that. They are wrong, Sakho is not in the eyeline of the goalkeeper.

"Neil Swarbrick could only guess he might be in front of the goalkeeper. Sakho is running away from goal and lets the ball through his legs - 99 out of 100 are given as a goal this year. I am totally and utterly confused."