MILAN – Englishman Mark Clattenburg is the designated referee for Atletico-Milan in the second-leg of the last-16 Champions League tie tonight at the Vicente Calderon at 20.45. He will be assisted by Mr. Beck and Mr. Burt who are also both from England. The additional assistants are: Mr. Marriner and Mr. Probert. The fourth official will be Mr. Collin.