Liverpool must hit the ground running in their Champions League opener against AC Milan tomorrow morning (Singapore time), as a tough group that includes Atletico Madrid and Porto will leave no room for error, Reds boss Juergen Klopp said yesterday.

The Reds and Rossoneri contested two finals in 2005 and 2007, each winning one, and Klopp said the Group B fixture at Anfield was among the "must-watch" games in the first stage of the competition.