West Brom manager Alan Pardew was critical of the application of the Video Assistant Referee system during his side's 3-2 FA Cup win over Liverpool at Anfield.
Three major incidents in the first half alone required the intervention of technology - including the first time a match referee has used a pitchside television replay.
And although it eventually led to the correct decisions being made, the time it took - with almost four minutes elapsing between Mohamed Salah being fouled and Craig Pawson awarding a penalty which Roberto Fimino missed - left supporters and players on all sides angry and frustrated.