Didi Hamann has fired a warning at Liverpool's players tonight.
"All eyes this time around will be on Diego Costa. His passion and his fire is a big part of how he plays the game, and if you take that away you will damage his influence on the match, but at the same time it's important to channel that aggression the right way because he will keep picking up silly bookings and that will go on to hamper his team.
"I'm all for a physical battle, but sometimes his antics are too much. If he can control his temper a little more he could be even more effective," he told Paddy Power.