That’s because it will be one of the first two Champions League matches – the other being Roma's home game against Porto – in which the Video Assistant Referee (VAR) will be in operation.
While this will be the first time VAR has been used in a European match in England, it has already made its debut at Old Trafford, in last month's Emirates FA Cup tie against Reading.
On that occasion, the system led to the award of a penalty scored by Juan Mata; the same United player had previously been on the wrong end of a video-assisted decision, when he had a goal contentiously ruled out for offside against Huddersfield last season.