Jessica Harrington and Robbie Power followed up their Gold Cup success with Sizing John when Rock The World took the last race of this year's Cheltenham Festival, the Johnny Henderson Grand Annual Challenge Cup.Power charged through on Rock The World (10-1) to lead at the final fence and storm up the hill to win from Gardefort ,with Theinval third and Dandridge fourth.It was Ireland's 19th win of the week to Great Britain's nine.