Arsenal fans raged at the controversial decision to allow Tomas Soucek's goal on Thursday.
Question marks were raised over whether the ball had gone out of play before Jarrod Bowen knocked it back to his teammate.
Video replays offered no conclusive evidence over whether the ball had crossed the line or not.
The decision stood because it had been given on field, but that did not stop the subject from being hotly debated.
beIN Sport now claim that technology has now shown conclusive proof that the ball was, in fact, in.
Their technology appears to show a slither of the ball was still on the line before Bowen hooked it back.
«I haven't seen it, the only thing they [the officials] said was the image was not conclusive,» said Arteta in his post-match press conference.
«It's just a shame that the technology that we have is not that clear that we can say it's out of play. It's done, it's gone and there's nothing we can do about it now.
»So what we have to do is without that, win the game, and with the situations we had today, we had more than enough."
Arsenal went on to lose the match 2-0 as they missed out on a chance to go top of the Premier League.
Konstantinos Mavropanos scored the second goal against his former club as David Moyes side went up to sixth.
HERE IT IS...
Was the ball in or out for West Ham's opening goal against Arsenal?@Richardajkeys