CREATE TABLE table_56588 ("Outcome" TEXT, "Date" TEXT, "Surface" TEXT, "Opponent" TEXT, "Score" TEXT)

What suface during the game that had Yevgeny Kafelnikov as an opponent?
SELECT "Surface" FROM table_56588 WHERE "Opponent" = 'yevgeny kafelnikov'
SELECT "Surface" FROM "table_56588" WHERE "Opponent" = 'yevgeny kafelnikov'