CREATE TABLE table_name_91 (lost INT, win__percentage VARCHAR, opponent VARCHAR)

What is the largest number Lost to david nalbandian with a Win Rate of 20%?
SELECT MAX(lost) FROM table_name_91 WHERE win__percentage = "20%" AND opponent = "david nalbandian"
SELECT MAX("lost") FROM "table_name_91" WHERE "20%" = "win__percentage" AND "david nalbandian" = "opponent"