Real Madrid are not sure how long Xabi Alonso will be absent after the midfielder limped out of the FC Zurich game with an ankle injury.

The injury came as he slipped trying to challenge Johan Vonlanthen in midfield, with Fernando Gago eventually coming on in his place in the 59th minute.

The 27-year-old Spaniard, who signed from Liverpool for £30m in the summer, looked to be in great pain as he left the pitch.

But Real's doctors say it is still "impossible" to know how long Alonso will be out for as the inflammation has not reduced and the player now faces new medical tests in Madrid to ascertain the extent of his injury.