Hillsborough match commander David Duckenfield has accepted his failure to close the tunnel was the direct cause of the death of 96 people in April 1989.
Giving evidence during the new inquest into the disaster, Mr Duckenfield said it had been the most difficult period of his life to admit his professional failing led to the deaths.
The barrister representing 75 families of Hillsborough victims, Rajiv Menon QC put to David Duckenfield that his leadership was "woefully inadequate from start to finish".
Duckenfield replied: "I disagree, Sir."
Menon said: "Your mistake was the most terrifyingly bad mistake... It was negligent and ultimately it caused the death of 96 Liverpool fans."
Duckenfield replied: "No sir... It is my view that it was an oversight, a mistake. I didn't view it as negligence and certainly never gross negligence."
Hillsborough match commander accepts his failure to close the tunnel was the direct cause of the death of 96 people in April 1989.
The police match commander at Hillsborough has said he thinks there was no conspiracy about the disaster.