Manchester United are among the top clubs monitoring £80million-rated Lazio midfielder Sergej Milinkovic-Savic. But Old Trafford spies had a wasted trip to Rome on Thursday to watch Sergej in Europa League action against Steaua Bucharest. The 6ft 4in Serb, whose agent is former Chelsea striker Mateja Kezman, was stuck on the bench as Lazio won 5-1. Old Trafford boss Jose Mourinho is anxious to bring in a commanding midfielder with Michael Carrick retiring and Marouane Fellaini expected to leave in the summer.