It will be difficult to talk to your child about their cheating but one way to present the information you wish to discuss is to deliver it in the third person.
The feedback given will appear less advisory and confrontational if delivered in the form of a story involving another person.
You could tell a story about a fictitious young player who became overly concerned about the result of matches and sadly felt that they were being judged by whether they won or lost. This difficult and sometimes unrealistic goal of winning matches coupled with the feelings of a lack of total control to influence the result of a match resulted in the player becoming anxious and fearful.
The player’s distorted thinking about what the outcome of the match meant and his doubt in his ability to win the match resulted in him calling some balls out that were in. Notice that no mention of the word cheating is used as this would be an interpretation of the fact that a ball which landed in had been called out.
Another approach is to reverse the story and present it from the perspective of the opponent of the player who is cheating. It might go something like this: “I remember being told by a coach about one of his good young players who was getting frustrated and annoyed when he thought that his opponent was calling balls out that he thought were in.
The coach asked his player to think of some reasons why the opponent might be calling balls out that were in, which would be helpful to him (the player). This encouraged the player to think of positive reasons, reasons which would benefit him, for why his opponent was behaving in this way.”
You could also try role-reversal: ask your child what they would say to one of their friends if they knew they were cheating. Only once these methods have started a conversation about the issues should you move the conversation on to focus on them.
Elicit from your child how they might apply the facts. Now is the time to use the word ‘you': “What do you make of this? Do you see anything in what I have said that may help you?”
Lastly, look at yourself. The problem may be with you. Check that your behaviour reinforces that the outcome of the match is not a key factor and that your child as a person is not being judged based upon the outcome of their matches. For more information on this see the Me-We Boundary article