Ruby and Leo were a skilled ping-pong team, and got along well with each other. They were both thrilled to get Sweet Pea and Hairy. Unfortunately, the pups' animosity towards each other rubbed off on Ruby and Leo, causing them to argue and fight. As a result, their next ping-pong match went badly, until Sweet Pea and Hairy (who had resolved their differences) inspired them to work together, and Ruby and Leo went on to win the match.
Leo and Ruby are clearly opposites to match up with Sweet Pea and Hairy. Seven year old Ruby was matched with girly, princessy Sweet Pea, while nine year old Leo was matched with tough, sporty Hairy.