At www.TennisRace2Win.net We also offer the chance to use the CROSSOVER system which basically allows players of a younger age to challenge older players. Please note that this is a great motivational tool but not accepted in National Ratings scoring systems until yellow ball levels are applied.
This is good for mini tennis upwards
(Red to Orange, Orange to Green or Green to Junior11+, Teenager to Adult)
The rules are simple, you can challenge 'up' but not 'down', and the challenge must be under the rules of the higher player (i.e. Orange challenges a Green and plays Green ball and Green scoring system)