There are some managers who would have taken Saturday's result at Ibrox with a shrug of a shoulders given that the league has been won and the team are still 10 points better off than the one that cuffed them 3-0.
But if we've learned anything from the last 20-odd months, it's that Ange Postecoglou is not that kind of guy. Make no mistake, Celtic's manager won't disregard the result or his team's performance in Govan at the weekend.
He might not have been ranting, raving or kicking tea cups around the visitors' dressing room. In fact, it's unlikely that he'd have shown signs of being visibly angry. But behind the cold hard stare and the stubble on his chin and cheeks, there will have been an uncompromisingly hard assessment of the facts that might add up to bad news for some of those at Celtic Park who have been happy to hang onto the coat-tails of the stalwarts who have driven the champions to the brink of another Treble.
Postecoglou knows he can put his mortgage on the likes of Cameron Carter-Vickers, Callum McGregor - although more of him later - Reo Hatate and Kyogo Furuhashi playing to the standards he demands. But on Saturday, with the league sewn up, the Aussie threw Alexandro Bernabei, Yuki Kobayashi and Oh Hyeon-Gyu into a Bear pit to see how they'd react.
Fifty-two thousand Rangers fans, no Celtic support. A test of their mettle as well as their maturity. The Argentine, Japanese and South Korean were a long way from home in every sense and way out of the comfort zone of cameos against the lesser lights in which they've looked happy enough.
He didn't get the answer he was hoping for. But he got one that will tell him that these fringe players are nowhere near ready to take his club to the places he has planned for it. Look, this trio of young players didn't lose Celtic the game on their own.
But it's not unreasonable to assume that Celtic would have been better with Greg Taylor, Carter-Vickers and Kyogo in their ranks. Alastair Johnston is also an upgrade on Anthony Ralston. If he wasn't, the Scot would be in the team before the Canadian.
If Postecoglou is looking for like-for-like in his ranks when one of the main men drops out, he has yet to find it and that's why more than a little dabbling will be required in the transfer market this summer. He was always going to be looking to add genuine quality for an assault on Europe that has been the only thing missing from Postecoglou's impressive stint in Scotland, but now he might just be thinking that his back-up players aren't up to the standards he needs.
They are young and will get better. He may well keep them around to develop further, but in the here and now, they failed a massive test at the weekend. That said, another poser for Postecoglou will be to come up with a way of making McGregor a bigger influence against Rangers because Michael Beale seems to have found a method of keeping the Celtic captain out of possession for long periods of the game.
Beale, recognising McGregor as the fulcrum of the Celtic team, has used Malik Tillman and now Todd Cantwell to hound him when he has the ball but also seems to have worked out a strategy that forces the Joe Hart and the centre backs to build from the back using their full backs - who are also pressed high and hard - rather than playing out through their captain.
The Ibrox ploy worked reasonably well in the last two games, but its effectiveness was overshadowed by the fact Celtic still won. On Saturday, Beale got both - his tactics right and the result. And yet, he too still has much to ponder.
If Rangers win their three remaining games this season, they'll get to 94 points. Celtic won the league last term with 93. That will tell him he's got a decent side, but in a league where he can't rely on others to nick points off Celtic, he needs a team that will do it for themselves, while still taking care of the others with the ruthlessness shown by their rivals.
The likes of Ridvan Yilmaz and Rabbi Matondo looked the part at the weekend, but can they be relied to do it at Celtic Park when the roles are reversed? Yilmaz? Maybe. Matondo? Not so sure.
The same goes with Fashion Sakala, who seems perfectly capable in front of goal when his team is a couple in front and he can notch to make it three or four nil. But give him a chance in the heat of battle, with the pressure on against Celtic and the Zambian has cracked twice this season.
He can't be relied upon and if Rangers want to improve, they'll need better. Beale is working on it. The Rangers side that starts next season won't bear much resemblance to the one that finally came good too late at the weekend.
Those who aren't there will have only themselves to blame for failing to cut it when it really matters. They might like to think they are very different, but in that regard Rangers and Celtic are eerily similar Being good enough to beat the rest is one thing, but if you're not good enough to get on top of your opponent from across the river, you're really not that much use to Beale or Postecoglou.
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