Portugal boss Roberto Martinez has praised the impact of one Manchester United-linked manager who has transformed his team into “really difficult” opponents to face on the pitch. Manchester United manager Erik ten Hag is awaiting to learn the fate of his long-term future at Old Trafford ahead of the club’s pre-season tour. The Dutchman signed off his second season at Old Trafford with major silverware after United sealed a stunning 2-1 win over Manchester City in the FA Cup final. Despite his success with the FA Cup, Erik ten Hag faced mounting criticism – and pressure – over United’s lacklust…