Serena Williams is the most dominant women's tennis player in the last decade. When she is focused and on top of her game she imposes her will on her opponent. Her sheer physicality and sense of belief, while being abstract feelings, win her points, games, and matches.
What I appreciate most about Serena is her self-belief. She believes that she should win every match she plays and is going to win or lose on her terms - playing her game. I believe this quote sums up well the deep well of self-belief that makes Serena Williams an all-time great: