Arsenal head coach, Mikel Arteta, has hit out at Video Assistant Referee (VAR), following their 1-1 draw with Sheffield United on Saturday.
Gabriel Martinelli fired the Gunners in front just before half-time, but John Fleck equalized seven minutes from the end.
Arteta believes his side should have been given the chance to double their lead before conceding.
Early in the second half, Nicolas Pepe went over Jack O'Connell's outstretched leg inside the box.
But referee Mike Dean waved away the protests and VAR did not get involved.
"I think it's very clear. It was the same as with Chelsea, very clear. I don't know how many tools do we need?
"A lot of things happen and the challenge is getting bigger and bigger because we are getting a lot of bad surprises every day with some injuries and suspensions.
"But we are up for it whatever we have we have we will try our best every time we get on that pitch and we did that today," Arteta told beIN Sports.