England boss Fabio Capello urged caution after his team's favourable World Cup draw which saw them joined in Group C by the United States, Algeria and Slovenia.
Capello's side will kick off their campaign on Saturday, June 12 against the United States in Rustenburg - where they are thought to be holding their training camp.
Their second and third matches will be in Cape Town against Algeria and in Port Elizabeth against Slovenia.
Capello told Sky Sports News: "We know two of the teams - the United States and Slovenia - from friendly games but we don't know Algeria. With the draw, people will think it is easy but I think we have to respect all of the teams.
"I know from my experience as a player that when you play here (in the World Cup) the pressure is different and the mentality is different. We have to respect the teams we have to play against.
"For me, no groups are easy. We have to play the first game which will be the most difficult. If we win the first game then in the second you play in a more relaxed way because you don't need the points to qualify.''
As for how much he knows of Algeria, Capello was brutally honest. "Nothing,'' he said. "I saw only some moments of the play-off games against Egypt. I saw goals they scored but not too much to understand much about them. For me it's important to see a lot of videos of games they have played.''
Capello revealed England are likely to face Egypt in a friendly on March 3 as preparation for facing Algeria.