Thrown in at the deep end is one way of describing the experience of Paolo Tagliavento and his colleagues at the weekend in officiating the World Cup qualification Group F fixture between Scotland and England.
It's unlike any other fixture, pure and simple, and unless this hairdresser from central Italy had been put through every clasico in Serie A and La Liga plus the big London, Liverpool and Manchester derbies, he could hardly have known what to expect at Hampden Park.
There are England players too, by the way, for whom the atmosphere will have been something entirely new, and although Tagliavento broke one of my own golden rules for such fixtures, in which I've been privileged enough to take part myself, I had to take my hat off in the end.
I always feel the ref must be lenient early on, when all the players out there are pumping and the tempo is in danger of running away from you, until he gets to the point where he says, “OK guys, enough is enough!” Anthony Taylor got it right at Wembley, for example, and the lad Moses had to go when he was caught red-handed with his dive in the FA Cup Final.
In a way, Tagliavento made a rod for his own back by booking Scott Brown in the opening minutes, but I have to admit he had a good game, and, although he could have sent Brown off later for a challenge on the same player, it was one of those that some give and some don't and he obviously decided to play the lenient card the other way round!
I did not think it was a penalty when Leigh Griffiths and Kyle Walker clashed in the 54th minute, but it was probably another 50/50 decision where there are plenty of others who saw it differently.
One lucky boy was certainly Gary Cahill, who got away with the kind of play-acting routine which I hope might be increasingly difficult to get away with in future as video scrutiny plays a greater part in the game.
England boss Gareth Southgate needed to make that change down the right and must have thought his substitution had won him three points after Alex Oxlade-Chamberlain scored his side's first goal in a game both sides were desperate not to lose.
Personally I'm all for my old team-mate Gordon Strachan staying as Scotland manager. He will also feel he was proved right, having made the call to snub the experience of Darren Fletcher and load up on Celtic players, of whom I thought Tierney and Armstrong were outstanding, despite their little mix-up.
The Scottish lads will no doubt have been kicking themselves because, having scored the first goals England had conceded in qualification, they should really have gone on the counter and made it 3-1 just prior to conceding a sucker punch to Harry Kane with seconds left on the clock.
At least we were not left casting doubt on the wisdom of appointing our Italian friends in light blue on the day. As a player, a supporter and I'm sure, as a manager too, you just want to feel the referee and his own team know what a game of this unique profile means. And Paolo passed the test.
Until next time you can catch me on the Alan Brazil Sports Breakfast every week day on TalkSPORT, 6-10am.