But the Frenchman insists that England will only make the next stage if they play with more freedom.
Fabio Capello's squad has come in for heavy criticism since they were held to a goalless draw by Algeria in Cape Town last Friday.
Their opening draw against the United States means that England have to beat Slovenia to guarantee a place in the last 16.
But their preparations have been hampered by rumours of discontent within the England ranks.
The unrest has cranked up the pressure ahead of Wednesday's decisive game in Port Elizabeth.
But Wenger expects England to go through - and to get stronger as the tournament continues.
"I think England at the moment are not at their best but they still should go through," Wenger told Arsenal.com. "They looked inhibited against Algeria and they played against a team that tried to defend very well.
"I don't know if they peaked in qualifying and certainly they need to play with a little bit more freedom. But any team who does well at the World Cup, none of them peaks in the group stage.
"To do well at the World Cup you start and then become stronger and stronger. England started slowly so will they become stronger and stronger? That is the question you need to wonder about and the question they need to answer."