Below is the list of tables from the database along with their columns and datatype. Need to generate an accurate SQL query for the question.
Only use the columns present in the respective table. Only use the columns which are required to generate the SQL query. Only use table joins if required and not otherwise.

### Tables ###
TABLE: CREATE TABLE table_name_91 ( lost INTEGER, win__percentage VARCHAR, opponent VARCHAR )

### Question ###
What is the largest number Lost to david nalbandian with a Win Rate of 20%?

### Accurate SQL ###

SELECT MAX(lost) FROM table_name_91 WHERE win__percentage = "20%" AND opponent = "david nalbandian"