Clijsters's biggest rival was Justine Henin, who grew up in the French-speaking part of Belgium. They have been regarded as having little in common except their nationality and their relationship has varied over time. Their rivalry began during their junior years when they were both considered promising young talents. They started out as friends and won the Belgian Junior Championships as doubles partners at ages ten and eleven respectively, despite only being able to communicate with hand signals due to Clijsters not knowing French and Henin not knowing Flemish. However, their friendship began to fade by their mid-teens, leading to disputes that their coaches would try to keep out of the media. Clijsters attributed this deterioration in part to one of Henin's coaches telling Henin, "she had to hate all of her opponents, and only then could she win." She also acknowledged they had very different personalities.