Abstract: An accessory that is readily around a tennis player's waist holds enough tennis balls to effectively play a game, but not too many so as to crowd the player's stroke. A bag made of nylon has an interior volume which holds the tennis balls, accessible through an opening with a piece of elastic biasing the bag closed at the opening. A nylon cord attached to a key ring is sewn to the bag so that the key ring extends into the interior volume adjacent the opening. The front and back panels making up the bag are preferably folded at their side edges, and first stitching is provided at a first fold and second stitching at a spaced location from the first fold, for maximum strength and durability. A nylon pouch large enough to hold a cell phone or eyeglasses may be attached to the back panel of the bag so that the pouch is hidden when the bag is worn on a belt around a human's waist with the front panel of the bag facing outwardly.