CREATE TABLE table_1918850_2 (surface VARCHAR(255), championship VARCHAR(255), score_in_the_final VARCHAR(255))
state the number of surface where championship is australian open and score in the final is 6–3, 4–6, 11–9
    
SQL: SELECT COUNT(surface) FROM table_1918850_2 WHERE championship = "Australian Open" AND score_in_the_final = "6–3, 4–6, 11–9"