The heat of Al Khor was always going to spell trouble for Croatia's ageing team, but the vitality of Morocco proved to be just as challenging.
Both were mountains which stood in front of Luka Modric at the isolated Al Bayt Stadium, the only one of the eight World Cup venues without a close connection to the centre of Doha.
But Modric has scaled far higher climbs before of course.
He is the little magician who was rejected by Hajduk Split for being too small, and went on to wrestle the Ballon d'Or from the dual clasp of Cristiano Ronaldo and Lionel Messi.
He's also sparkled at Tottenham, won five Champions Leagues with Real Madrid and, in that same Ballon d'Or winning year of 2018, guided Croatia to the World Cup final in Russia, a game away from what would have been one of the all-time great football stories.
However Modric is 37 now, and although this tournament's move to the winter makes it slightly more possible that we could see him in the US, Canada and Mexico at the age of 40 in 2026, it is very unlikely.
This is a last dance on the global stage then, but worryingly for him the same could be said for a few of his important teammates.
Ivan Perisic is 33 now, as is Dejan Lovren, while Andrej Kramaric - the one-time Leicester City man - is still starting for his country at 31, and Marcelo Brozovic, although excellent, is also in his 30s.
None of them are over the hill of course, but they are not exactly at the bottom of it either, and that always looked to be an issue against this Moroccan side full of running.
And so it proved.
Of course Croatia looked to Modric throughout this match, and if they didn't give him the ball then he demanded it.
There was a superb corner that dropped to the masked Josko Gvardiol and invited him to shoot, and then there was the silkiest of balls through to Nikola Vlasic who couldn't quite take it in his stride.
These are the players, plus others, who Croatia need to keep up standards in the years to come as this 'Modric generation' fades away, a fade which could increase off the back of difficult and hot afternoons like this.
Half an hour into the game a scoreboard animation showed that Modric had completed 100 per cent of his passes, but many of those were coming from deep as he sought to inspire his side and get those around him running, while also doing plenty of running himself.
Running here is hard though, especially at 37 and against opponents like this.
Modric's radar would soon go awry and the collectors item's came just before the hour mark when he shanked a pass straight out of play like a out of form golfer.
Croatia had their chances, with Morocco's excellent goalkeeper Yassine Bounou - known as Bono when he players for Sevilla - equal to them, but they lacked the physicality they had in Russia four-and-a-half years ago, and that might well end up costing them.
