O'Neil branded defeat at Brentford the worst of his managerial career.
Lemina said: "The way we are playing, the way we are defending right now is going to get us in relegation and we have to be honest about that right now."
He added on O'Neil: "No, Gary is not the problem. He is doing really well. If you say Gary O'Neil is the problem then you are liars and cheaters, because he has given us a lot. A lot of things we didn't have before.
"He has given a chance to a lot of players and now we have to give it back to him, because at the moment we are not giving it back.
"I think the fans really love him as well. Now it is a point of view because of the results, which is understandable.
"It is not about the coach, it is not about anything but ourselves
"After the international break we need to be honest again with ourselves and try to work things out and be committed to the plan, that's it.
"We have just one point, it is really bad but I am really sure that we are going to come back from this. It is going to be tough after the international break, mentally, but we have to believe in ourselves."