Kate, 30, who played hockey in school and even served as her high school's team captain, joined in the game with players from Team GB, as part of her role as ambassador to the British squads.
Confessing to pre-game jitters, she said, "This is going to be so embarrassing. My brain thinks I can do all these wonderful things but my body just doesn't play ball."
Donning coral pink jeans and grey GB sweatshirt and Adidas sneakers, Kate finally scored a goal after three or four attempts.
"Wow, that was no pressure then," Kate said – somewhat sarcastically. "I was determined to keep on going until I scored."
James Whatling / Splash News Online
Later Thursday – after a quick outfit change into a grey Orla Kiely dress and black pumps – Kate spent time with her in laws, Prince Charles and his wife Camilla, Duchess of Cornwall, at Dulwich Picture Gallery, where she was introduced to The Prince's Foundation for Children & the Arts.
Greeted by 150 cheering school children waving Union Jack flags, the royal trio met with the children, teachers and artists involved in the charity, which aims to help disadvantaged children relate to art.