CREATE TABLE table_22091 ("Edition" TEXT, "Round" TEXT, "Date" TEXT, "Partnering" TEXT, "Against" TEXT, "Surface" TEXT, "Opponents" TEXT, "W\\u2013L" TEXT, "Result" TEXT)

What country did Gil play against on 21 23 september 2007?
SELECT "Against" FROM table_22091 WHERE "Date" = '21–23 September 2007'
SELECT "Against" FROM "table_22091" WHERE "Date" = '21–23 September 2007'