CREATE TABLE table_71831 ("Date" TEXT, "Tournament" TEXT, "Surface" TEXT, "Opponent in the Final" TEXT, "Score in the Final" TEXT)

When did Mathieu play against Antonio Vei ?
SELECT "Date" FROM table_71831 WHERE "Opponent in the Final" = 'antonio veić'
SELECT "Date" FROM "table_71831" WHERE "Opponent in the Final" = 'antonio veić'