Referee Angus Gardner has admitted that he was wrong not to penalise England co-captain Owen Farrell for his tackle on South African Andre Esterhuizen earlier this month.
The Australian official called for a TMO review which ruled Farrell's last-minute "no-arms" tackle on Esterhuizen to be legal and secured England's 12-11 victory over the Springboks at Twickenham.
Speaking on the Will Greenwood podcast, Gardner admitted he should have awarded South Africa a penalty.
"I think in hindsight now, having discussed it with some other referees... I think the general consensus would be that a penalty was probably the outcome there that should have been given," he said.
"The angles that I saw with the TMO, which were the head-on angles, showed a clear wrap of the front arm, but it was the back arm which got pinned.
"At this level the expectation is that we do get it right -- and that's what we're striving to achieve -- but we don't always."
Gardner attended the World Rugby Awards in Monaco where he received the award for the Referee of the Year.
Farrell was once again involved in tackling controversy after getting away with another "no-arms" tackle in England's 37-18 win over Australia at Twickenham last weekend.