Real on edge for Madrid derby away at Atletico

  Simeone, often described as playing with a knife between his teeth when he captained Argentina, has brought some of his uncompromising tenacity to Atletico who have lost only once at home since he arrived in the winter break. La Liga leader Real and star striker Cristiano Ronaldo, on the other hand, will have their nerves on edge after seeing a 10-point lead over Barcelona cut to four in the space of three weeks. Their latest slipup was a 0-0 draw at home to Valencia on Sunday.