CREATE TABLE table_16741821_8 (surface VARCHAR, opponent VARCHAR)
SELECT surface FROM table_16741821_8 WHERE opponent = "George Khrikadze"
พื้นผิวทำมาจากอะไรเมื่อฝ่ายตรงข้ามคือ GEORGE KHRIKADZE?
WHAT WAS THE SURFACE MADE OF WHEN THE OPPONENT WAS GEORGE KHRIKADZE?