England were 2-0 up and cruising to an easy win when Zlatan Ljubijankic reduced the arrears six minutes from time.

A first-half penalty by Frank Lampard was followed by a 62nd-minute strike from Tottenham striker Jermain Defoe but England were left hanging on towards the end.

"I was not happy to concede a late goal because the concentration was not good in the last four or five minutes," said Capello.

"We played too slow, we played long balls and didn't play the style I like.

"I want the players to focus and concentrate on every minute of the game."

Capello made four changes at half-time, removing Emile Heskey from the attack as well as replacing Steven Gerrard, Lampard and Shaun Wright-Phillips.

Defoe's goal will have boosted his chances of a place in the starting line-up against Croatia in their World Cup qualifier on Wednesday but Capello would not be drawn on whether the Spurs striker had done enough to get the nod ahead of Heskey.

"Heskey played a good game," said Capello.

"I had a chance at half-time to see a different style of play with two smaller players. I am still trying different things.

"I want to know a lot of things but Jermain always scores when he plays the second half. I want to use the time before the next game to decide. I am happy tonight. Friendly games are very important preparation for me.

"Slovenia were a difficult team to play against but I learned a lot about individual players but I cannot share anything.

"We had a lot of chances and we have no injuries."

Capello admitted that the could not see whether or not Wayne Rooney had been fouled for the penalty but Slovenia coach Matjaz Kek was unhappy with the penalty because it could have robbed him of his centre-half Bostjan Cesar for next week's World Cup qualifier against Poland.

Cesar was guilty of pulling Rooney's shirt but he hurt his ankle in a collision with the Manchester United striker.

"You can never be happy when you lose a game," said Kek.

"This match was a real test ahead of our qualifier against Poland.

"We were brave and played well. I am angry and disappointed with the injury but these things happen in football. We have probably lost Cesar for the game with Poland.

"You play a friendly match and then you lose a player, I am not angry about Rooney but about losing a player.

"The x-rays show that nothing is broken but the ankle is really swollen and we will wait and see over the next few days if he is able to play or not.

"England were better but our young players showed they can play at this level and the selection of the team will be tougher now.

"We now have to rest and regenerate the guys as best we can ahead of the Poland match.

"We wanted to stop the English passing game and we did that at some points but we did make some mistakes that we will have to correct in the future."