Below is an instruction that describes a task. Write a response that appropriately completes the request.

### Instruction:
WHAT WAS THE SURFACE MADE OF WHEN THE OPPONENT WAS GEORGE KHRIKADZE?

### Inputs:
table_name: table, columns: ['Edition', 'Round', 'Date', 'Against', 'Surface', 'Opponent', 'W/L', 'Result']

### Response:
SELECT Surface FROM table WHERE Opponent = George Khrikadze