CREATE TABLE table_name_88 (week_of VARCHAR, winner VARCHAR)

What is the Week when the winner was mary joe fern ndez 6 4, 7 5?
SELECT week_of FROM table_name_88 WHERE winner = "mary joe fernández 6–4, 7–5"
SELECT "week_of" FROM "table_name_88" WHERE "mary joe fernández 6–4, 7–5" = "winner"