Yesterday saw perhaps the best utilisation of the new Hawk Eye goal review system as Chelsea defeated Liverpool 2-1. Liverpool, 1-0 up at the time, conceded from a corner after Gary Cahill's shot was carried over the line by Simon Mignolet.
It was a goal that the referee would never have spotted without the use of the goal-review system, and one which even Chelsea boss Jose Mourinho looked surprised to go in.
But it would not be a surprise if Mourinho had a wry smile on his face when contemplating the goal, as this is not the only time that a goal-line decision has been crucial to a Chelsea v Liverpool tie.
Mourinho referred this week to the infamous 'ghost goal' in the fixture between Chelsea and Liverpool in the Champions League semi-final nine years ago.
Cleared off the line by William Gallas, but adjudged to have crossed the line by the referee that night, the goal from Luis Garcia proved vital in 2005. Liverpool won the game and went to the final. The rest, as you know, is history.
Mourinho has never won the Champions League with Chelsea and it remains one of his main aims at the club. 2005 is perhaps the closest he has personally taken them and to this day he still remembers the Garcia 'ghost goal' with a grimace.
So for this goal to count may have been a small touch of redemption for Mourinho.