Gareth Southgate believes England's game in Hungary on Thursday could be "pivotal" to their World Cup qualifying chances.
The Three Lions play their first game since losing on penalties to Italy in the Euro 2020 final and manager Southgate said his side, who top the group, must start all over again.
He told a press conference: "I think the two away games this week are both going to be hugely challenging.
"They're good teams. They're obviously pivotal games in terms of qualification.
"You can't predict what your hardest games are going to be, but we know that Hungary are a very good side and sit second in the group."
After Thursday's clash in Budapest, England face Andorra at Wembley on Sunday and then travel to play Poland on Wednesday.
Southgate, whose only injury doubt is Jadon Sancho due to a knock, said: "The team has gained confidence from what they achieved and the progress they've made, not only this summer, but over the last four years.
Here it is... your #ThreeLions squad for September! 👊 pic.twitter.com/wwjJEiVGz6 — England (@England) August 26, 2021
"But equally we have to start again. The journey to having the chance of another run like that in a tournament is under way. We have got to be at our very best.
"Mentally it's a good test for us. Away from home, 60,000 fans and a very good team we're playing against."
The Hungarian FA is facing UEFA sanctions for alleged racist and homophobic chanting by their country's fans during the Euros, but Southgate refused to be drawn on what action his players would take if they received similar abuse.
"We always prepare the team for everything really," he added. "We've done that this week, but we know we've had our own issues at home, so we're not really focusing on other countries, we're focusing on ourselves and making sure we get our own things correct.
"I don't think we should speak hypothetically. We know the experience we had before (in Bulgaria), but we're going to Hungary preparing for a game against a crowd that will get behind their team and we're looking forward to the challenge of the match. Everything else is speculation really."
