Cape Town - Everton boss Ronald Koeman issued a warning to Ross Barkley to step up his game after the midfielder put in a poor performance against Sunderland on Monday.
Frustrated with Barkley's inability to keep hold of the ball, Koeman substituted him at half-time and has since had a frank discussion with the England international.
"There was a reason to change Ross at half-time because he did not play well, he lost many balls and players of that quality can't lose those kinds of balls," the Dutchman said.
"We analysed the game as always and had individual talks. I had them with Ross and he needs to improve and, OK, we will see at the weekend."
The 22-year-old is having a rough time of it lately, having been left out of Sam Allardyce's squad to face Slovakia, but Koeman feels he needs to put that disappointment behind him and move forward.
"That is the past, in my opinion, what counts is what happens now," he added. "You get game time for your national team because you play at a good level for your club. It was one game what happened last Monday and he understands.
"I showed him the clips and there is no escape. Ross needs to be the key player between defenders and strikers. You look at his qualities and his position is to create. In all aspects he needs to improve but he is still a young player, no question."