Oldham boss Lee Johnson was in no doubt that Leyton Orient's equalising goal in the 1-1 draw should not have been allowed.
After the Latics took a deserved lead through Charlie MacDonald, Orient's leveller was awarded despite substitute Shaun Batt clearly being in an offside position.
The match officials ruled that Batt had not got a touch on Kevin Lisbie's low shot, leaving Oldham furious that they were denied their first win in six games.
Johnson said: "How can the referee and linesman not see that the lad touched the ball before it went into the net?
"He touched it and it was offside. We've given a fantastic performance and yet again we've been undone by poor officiating.
"The lads have come in inspired by the way they played but also demoralised by something outside of their control.
"Things aren't going for us at the moment and the officiating all season has been really poor.
"I'm proud of the way we played. We gave it everything and were unlucky not to score more goals.
"We had Orient penned back in the first half. With performances like that, it will definitely turn for us."