Whenever Celtic or Rangers lose in domestic competition, we in the media conduct a kind of national inquest, almost akin to a murder having taken place.

The quest has started already to reach firm and fast conclusions after St Johnstone’s excellent League Cup win over Rangers at Ibrox on Tuesday night.

Amid the groping around for ideas a couple of obvious ones spring to mind:

Well, what a gulf in class there is between the top of the Championship and the Ladbrokes Premiership…

Or:

Well, that’s Mark Warburton and Rangers exposed, they’ve got a long way to go before becoming top-tier material…

Neither of these lunges for meaning look persuasive. They are certainly not as convincing as the more simple truth that St Johnstone played some excellent football on the night, and have a real gem in Michael O’Halloran, one of Scottish football’s best signings in years.

O’Halloran has wonderful ball composure and pace to burn over 15 yards when he needs it. Danny Wilson discovered this when stretching and failing to stop O’Halloran from setting up St Johnstone’s opening goal, and from scoring a third.

Little wonder O’Halloran told me the day before the match: “I’m not nervous at all about going to Ibrox to face Rangers. I feel more excited than anything.”

St Johnstone’s excellence in passages of the game did for Rangers, who couldn’t cope. But it is stretching it to say that Warburton’s team were thoroughly second-best on the night, let alone “out-classed”.

This is ludicrous stuff.

Rangers are making steady progress under their likeable manager, and Tuesday night’s defeat doesn’t change that. Most Rangers supporters, as hard as defeat is to take, see their current team and manager as a marriage in progress, and nothing has changed that.

Yes, St Johnstone are playing at a higher level, and that looked obvious at various moments. But if you pitted those same two teams against each other 10 times consecutively, my hunch is you’d have a mixed bag of results.

It was a tremendous night for St Johnstone. They have a gem of a manager in Tommy Wright, who respects his club, respects its fan-base, and has brought a sustained excellence around McDiarmid Park since he took over from Steve Lomas in June 2013.

Not least of Wright’s work was in bringing O’Halloran, a talented player who was adrift in football, to the club. And it is worth asking: do Rangers right now have a player who can emit such danger and carve open opponents?

Probably not. But Warburton is three months into his Rangers project. These are the early foothills of the Warburton journey in Glasgow.

It is certainly true that, in scoring so freely, and whipping opponents as they have done, you have to acknowledge that Rangers are playing in a league well below their station. It would be surprising if, being managed competently, they didn’t dominate in the way they are.

But there are rafts of current Rangers players who would keep their places in a Tommy Wright St Johnstone team. There is no major gulf in class. On another night that 3-1 win for the Saints could easily be reversed.

It doesn’t do to read too much into a single League Cup 90 minutes. There is so much more evidence to be had.

The real evidence will come when Rangers play in the top tier next season. Now that really will be persuasive, after watching a whole season of football.

Players such as James Tavernier and Martyn Waghorn have shone for Rangers – and it has been exciting to watch. What is more intriguing is whether players of their ilk, currently running riot against poorer league opponents, can remain effective Rangers players as the club ascends to the top flight, to winning trophies, and to being in European football.

On this journey, the Ibrox heroes of today may have to be jettisoned along the way. Their glass-ceilings may become more obvious, as opponents become better.

It’s also weird the way Wright continues to excel for the Perth Saints, and yet he is hardly mentioned for any bigger job that comes along. Wright’s name is always strangely missing from the lists.

Which is just how the St Johnstone fans like it.