The audio recordings of discussions between the match officials around Luis Diaz's disallowed goal against Tottenham have been made public.
Video assistant referee Darren England did not overrule when Liverpool's Diaz was wrongly flagged offside.
In the audio, England says the check is "perfect" before swearing when he realises a mistake has been made.
After releasing the audio on Tuesday, PGMOL, the governing body for referees, said the error was a result of a "lapse of concentration and loss of focus".
What the officials said as they analysed the incident
The match between two of the Premier League's leading teams was goalless when Diaz thought he had put the visitors ahead after 34 minutes.