CREATE TABLE table_60477 ("Edition" TEXT, "Round" TEXT, "Date" TEXT, "Surface" TEXT, "Opponent" TEXT, "Result" TEXT)

Who was the opponent on april 24, 1999?
SELECT "Opponent" FROM table_60477 WHERE "Date" = 'april 24, 1999'
SELECT "Opponent" FROM "table_60477" WHERE "Date" = 'april 24, 1999'