Crystal Palace academy manager Gary Issott has warned opponents that there is more to come from the mercurial Wilfried Zaha - the latest addition to the England squad.

Zaha, called up by Roy Hodgson for Wednesday's friendly against Sweden in Stockholm, got his chance when Wayne Rooney, Theo Walcott, Jonjo Shelvey, Kyle Walker and Aaron Lennon withdrew through injury.

The winger, who celebrated his 20th birthday on Saturday with a 2-1 Championship win at Peterborough, has bagged four goals this season to help Palace sit pretty at the top of the Championship table.

Issott said: “It is excellent news and recognition of Wilfried’s ability. He has been outstanding for two seasons and has been instrumental in where we are at the moment.

“He is such a hard-worker and will do what you want him to do in terms of tracking back and doing the defensive side of things.”

He added: “But he has that unpredictability going forward. We allow him that freedom – with other players you coach about the one-twos going forward, getting in the rights places – but with Wilfried it is all about giving him that freedom, you have to leave him to it.

“He is only 20, and players don’t really understand football properly until they get to about 23 or 24, so he will get a better understanding of the game as he develops. There is more to come from him, I am sure.”

Issott, who has seen Victor Moses and Nathaniel Clyne rise through the acadmey and go on to play in the Premier League, remembered the moment Zaha broke into the first team.

“He got his chance when George Burley asked us in the academy to hand over our best player for a pre-season with the first team.

“We chose Wilfried and, to be honest, we expected him to be back in a couple of weeks but that was it.

“His journey was a strange one. You normally know very quickly whether a player has that special ability. With Victor Moses, you knew he was going to be a first class player.

“But Wilfried was a late developer, at 14 to 15 years old, he did not stand out, there was nothing to suggest the player he would become. But he excelled in the U16s and when he went into the U17s he took off.

“When George [Burley] took him on, it was playing with seasoned pros and internationals that really helped him develop his game.”

He added: “Can he go all the way? Of course he can.”