The Mexican capital has been awash with green shirts as home supporters gather in their thousands before the knockout clash, but England fans who have followed the team to the capital remain cautiously optimistic.
Friends Graham, Tony and David - from Sunderland - have travelled to New York, Atlanta and now Mexico City in support of Thomas Tuchel's side, determined to see England's World Cup campaign continue.
For Sheridan, performances matter less than results.
"People think we've had one good half of football (against Croatia)," he said. "But I look beyond that because we've still been winning games. There's a lot to be optimistic about.
"This is going to be the hardest game, the Mexico game. If we get through that, I think we can go all the way."
Richie shares that view, insisting that progression is ultimately what counts.
"You've got to get the results at the end of the day, and that's the main thing," he said.
While England supporters have received a warm welcome since arriving in Mexico, David expects the atmosphere to shift if the hosts are knocked out.
"The people have been amazing so far," he said. "But I think that atmosphere might change a little bit if we win. That's what we've got to be careful about."
Steve and Debbie Stone have also followed England throughout the World Cup, including the pre-tournament warm-up matches. They have already booked flights to Miami should England reach the quarter-finals, while keeping a return route back to the UK in reserve if their run ends on Sunday.
"It's exciting being here," Debbie said. "Everyone's really hyped up about it. I'm just not sure if we'll cope with it in the stadium. I think the stadium is going to be mad."
The couple have followed England for two decades and Steve believes the match will provide one of the sternest examinations they have seen.
"The pressure on the players is high," he said. "We've been following England for 20 years and these are the kind of games you want to be at.
"We need to play better than we have done because after 60 minutes of the last game (against DR Congo) we're thinking we're not going to make it to Mexico. It was a relief that we got here, but we've got to improve."
His memories of England's penalty shootout defeat by hosts Portugal following a 2-2 draw at Euro 2004 remain vivid.
"The last time we went to a host nation game was Portugal in 2004 when they beat us," he said. "That was mental afterwards. They were banging drums, and we were going back to our accommodation like this (quietly) and they were (celebrating) on the streets.
"Obviously it'll be crazy here if (Mexico) win, but we've been to some pretty good games, but not a World Cup game against the host nation."
Having watched matches in both the United States and Mexico during the tournament, Stone said the contrast in football culture had been impossible to ignore.
"We watched a game in a bar last night (and) it's so different to watching a game in the States," he said. "People there are into it, but not really into it. Here, everyone's just mad for football. It's a great experience.
"I'm not sure I feel overly optimistic. I see from the bookies we're favourites to win tomorrow, but I'm not sure. I'm not sure about that."