Smash (1982)

Sexy Las Vegas showgirl Stevie Castle and society snob Celia Berryman are two tough-minded mothers of two very precocious young tennis champs. This unlikely duo meet and immediately clash at a tennis tournament which will name one of their daughters national champion. Meanwhile, young KC and Missy are caught up in their mothers' battle - until a mutual love of tennis draws them together to conspire to break away from the pressures of competition. The girls decide to spend 24 hours doing every wild and crazy thing they had ever dreamed up... and end up learning a lesson in grown up ways that will last them forever.