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.
Taking over cross-examination of Hillsborough match commander David Duckenfield, Michael Mansfield QC, said he was "reckless" by not recognising the risk of injury to fans.
Duckenfield replied: "It was purely an oversight in very stressful circumstances."
"I opened those gates and was solely focusing on those gates and looking at saving people from death," he added.
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.