England manager Thomas Tuchel has acknowledged that the high altitude in Mexico City is having a noticeable effect on his players, admitting to personal sleep difficulties and a slight headache in the lead-up to Sunday night's World Cup last-16 match against the co-hosts.

Mexico City sits 7,200 feet above sea level, a factor that is widely considered an advantage for the home team. Tuchel stated that the team felt the effects even during their training session at altitude.

"You know what, we feel it," Tuchel said during a press conference. "We feel it, even if we don't train. I felt a slight headache and in the hotel room through the day, didn't sleep as well as the days before."

He noted that the players also experienced the difference, especially in the initial stages of their training. "It's nothing that you cannot handle and cannot adapt (to)," he added. "The players felt it in the first minutes of the training session and the longer it went they could cope with it better.

"We cannot physically adapt, it's just impossible, but we are here one day before to experience it, to not have all the first-time experience tomorrow in warmup."

Tuchel anticipates a strong start from Mexico, a characteristic he attributed to playing on home turf. "It's not a coincidence that Mexico starts their matches on their home turf very, very strong, very front-footed, very aggressively. I think the first 15-20 minutes will be maybe the toughest for us. Once we overcome that, and we experienced that already today, we're in a good place."

Responding to playful questions about performance-enhancing methods, Tuchel dismissed notions of the team using Viagra to adapt. He also addressed historical context, specifically the 1986 World Cup match involving Diego Maradona's infamous "Hand of God" goal.

"Everyone remembers the (Diego Maradona) goal and the huge disadvantage for the English team," Tuchel said. "This is painful and still hurts but we are not here for revenge. It's the same stadium but it is not the same opponent. We are here to write our own chapters. We are ready to go tomorrow."

England is preparing to write a new chapter in their history when they face Mexico at the Azteca Stadium on Sunday night.