Arsenal manager Arsene Wenger feels North London rivals Tottenham have a "50-50'' shot at dumping Real Madrid out of the Champions League.
The Gunners, finalists in 2006, failed to progress to the quarter-finals after losing to Barcelona last month, althougjh Wenger said "if everything went all right" in the second leg, Arsenal would have progressed.
However, arch-rivals Tottenham have proved the surprise package of this year's European competition, winning their group ahead of Inter Milan and then knocking out AC Milan in the last 16 to set up a clash against Jose Mourinho's side.
Real Madrid lost their first home game in 25 matches when beaten by 1-0 Sporting Gijon at the weekend, giving Spurs hope of a securing a famous result in the Bernabeu on Tuesday night. Wenger believes Harry Redknapp's men have nothing to lose.
The Arsenal manager said: "It is very open, it is 50-50. Who cannot be beaten? If everything went all right, Barcelona would be out today. If it had stayed 11 v 11, I am convinced of that.
"Why can't Spurs beat Real Madrid. Real Madrid has a disadvantage to play the first game at home, Spurs at home look to be strong. It is a real 50-50 game.''
Spurs also have their own injury worries, as defender William Gallas looks increasingly doubtful to make the trip to Spain after breaking down with a knee injury, while key man Gareth Bale is struggling to recover from a hamstring problem.