This follows an undefeated season for the team, which celebrated a 45-0 win against opponents Bredon Hill Academy, from Worcestershire.
The school’s director of sport, Sam Stoop, said: “To get to the quarter finals of the National Cup is a tremendous achievement for the boys and the school.
“To win it in such emphatic style and progress into the semi-finals is absolutely incredible.
“We looked rusty in the first half but got into our stride after half time and showed what a class team we are.
“These boys are a real credit to the school and the games department and deserve this success.
“They are a delight to coach and let’s hope we can get to the final.”
Winchester House now faces Sandbach School, Cheshire, in the semi-finals.