Mexico await England in the World Cup round of 16 - and that is a massive task for England to take on in more ways than one.
The co-hosts have clearly enjoyed playing in front of their own fans this summer. They were one of just three sides to make it through the group stage with a 100% record, alongside France and Argentina.
Only Spain have managed to go the whole tournament without conceding a goal yet - and Mexico have played a game more, having already seen off Ecuador in the round of 32 while Spain await Thursday's clash with Austria.
Clearly, having a passionate, roaring fanbase cheering them on from all four corners of the stadium is going to be challenging for England.
But Mexico's home advantage is not just about playing on home soil. It's also about just how much earth there actually is underneath the stadium.
Sitting some 2,200m (7,218ft) above sea level, the Azteca in Mexico City is at over twice the altitude of England's highest peak, Scafell Pike; or 64% higher than the top of Ben Nevis, the highest point in the UK.
It's also a good 600 feet higher than Europe's highest stadium: the Omar Hitzfeld Arena in the Swiss Alps.
Playing at that kind of altitude - and in that kind of heat, on top - has a notable effect on players' respiration, focus, and ability to perform.
The playing field is not even in that regard, in that athletes who are used to training and playing at that kind of altitude are physically better accustomed to its demands - which is exactly why endurance athletes are fond of altitude training.
That could be an issue for Thomas Tuchel's side, because we dare say that Estadio Azteca is at a higher altitude than most, if not all, of the England squad have every played at before.
Mexico have meanwhile played three of their four games so far this tournament at Estadio Azteca, with the odd game out played at Estadio Akron...the second-highest stadium in the competition.
To put that into context, Atlanta's Mercedes-Benz Stadium is the closest to the heavens England have got so far this tournament. It sits just 320m (1,050ft) above sea level - around 15% as high as the Azteca.
The best advice for the Three Lions, then...get the game beyond doubt early and avoid extra time.
Easier said than done, we imagine.
