England's players will have no time to adapt to the altitude of Mexico City's Azteca Stadium before their World Cup last-16 tie against Mexico on Monday at 01:00 BST, head coach Thomas Tuchel has admitted – as celebrations in the Mexican capital turned deadly.
The Azteca sits 7,200ft above sea level, where thinner air means less oxygen reaches the bloodstream. Research suggests athletes need one to two weeks at altitude to acclimatise, but England will arrive only two days before kick-off.
“England face Mexico at 7,200ft altitude with no time to adapt, as deadly celebrations hit Mexico City.”
"It just takes too much time – it's physically just not possible to adapt," Tuchel said. "That is just a huge advantage that Mexico will have."
Mexico have played all four of their World Cup games at high altitude, three at the Azteca and one in Guadalajara at 5,000ft, giving their players a clear physiological edge.
England booked their place in the last 16 with a 2-1 comeback win over DR Congo, secured by a Harry Kane double. The victory set up the Monday morning fixture – the most antisocial kick-off ever for England fans, who must stay up until 1am to watch.
Meanwhile, the Mexican capital saw tragedy after the national team's 2-0 win over Ecuador in the previous round. City authorities said four people died: a 19-year-old woman, a 48-year-old woman and a 44-year-old man from suffocation, and a 30-year-old man from an epileptic crisis. More than one million people flooded the streets, mainly around the Angel of Independence monument.
Mayor Clara Brugada offered "most sincere condolences" and urged fans to "always celebrate with responsibility, care, and empathy".
England, seeking their first World Cup win since 1966, showed resilience against DR Congo. Tuchel dismissed the idea that pressure affected his side: "I did not see any of that. That is a very, very good sign." He added: "More obstacles may come, but we are ready for that." But the altitude and the early hour pose fresh challenges as the Three Lions head to the Azteca.