When Song struck the ball three West Ham players were in offside positions but none of them touched the ball .
The incident occurred when Song struck an impressive volley from 20 yards out that beat Arsenal 's Szczesny , only for the linesman to rule it offside .
When Song struck the ball three West Ham players were in offside positions but none of Arsenal touched the ball .
The incident occurred when Song struck an impressive volley from 20 yards out that beat Arsenal 's Szczesny , only for the linesman to rule it offside .