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_25442 ( "Outcome" text, "Year" real, "Championship" text, "Surface" text, "Opponent in final" text, "Score in final" text )

### Question ###
What is the amount of US open runner-up score?

### Accurate SQL ###

SELECT COUNT("Score in final") FROM table_25442 WHERE "Championship" = 'US Open' AND "Outcome" = 'Runner-up'