England goalkeeper Joe Hart expects Slovenia to push the side hard when the teams meet in a 2018 World Cup qualifier in Ljubljana on Tuesday.
Victories over Slovakia and Malta have propelled England to the top of Group F.
But Hart is taking nothing for granted given Slovenia were the only side to score against him during England's largely untroubled run in qualifying for Euro 2016.
England's 3-1 comeback win was followed by a 3-2 success in Slovenia and Hart said Monday: "It was probably our toughest two games of the group, especially at Wembley. They took the lead and it took us a while to get back into it. It was one of those tough internationals."
Hart, on loan to Italian side Torino from Premiership club Manchester City, added: "I think we then played them in mid-June and Jack (Wilshere) had an amazing game and scored two fantastic goals.
"We ended up really needing Wazza's (Wayne Rooney) cool, calm head to stick the ball away.
"It was a really good win for us and a really good game. We expect the same sort of game on Tuesday night.
"I played against one of their players last Sunday for Fiorentina, Josip Ilicic. He is a strong player with a good left foot.
"They have got some good players and they work well as a group. They have got a fantastic keeper so they are going to be good."
Meanwhile England captain Rooney trained as normal with the squad on Monday amid speculation he could be dropped by interim manager Gareth Southgate.
England's all-time leading goalscorer, the 30-year-old Rooney was booed by some home fans during the 2-0 win over Malta on Saturday and former national team captain Alan Shearer has led calls for him to be dropped.