CREATE TABLE table_40289 ("Week of" TEXT, "Tier" TEXT, "Winner" TEXT, "Runner-up" TEXT, "Semi finalists" TEXT)

What is the Week when the winner was mary joe fern ndez 6 4, 7 5?
SELECT "Week of" FROM table_40289 WHERE "Winner" = 'mary joe fernández 6–4, 7–5'
SELECT "Week of" FROM "table_40289" WHERE "Winner" = 'mary joe fernández 6–4, 7–5'