Lampard wants offside clarity

English referees Mark Clattenburg and Kevin Friend made a joint-decision to disallow a crucial goal for Porto in the Champions League last-16 draw against Basel on Wednesday because two of their strikers were standing in front of the goalkeeper.

The incident came just two days after referees allowed a Manchester United goal to stand in the FA Cup fifth round victory at Preston, despite Wayne Rooney impeding the keeper???s view and having to move out of the ball???s path to allow it home.

Lampard told Sky Sports: ???There isn???t an 100% rule, which is what we???ve seen in the last week.

???We can all talk about offside and disagree because there???s no conclusive rule. ??But if someone is affecting play ??? and the one for Porto was affecting the goalkeeper???s dive ??? then it???s offside.

???That was the right decision. The Rooney one on Monday night was the wrong decision.

???Every year the officials come down to each training ground and give out new rules and anything that???s changed from last year.

???But we can???t blame them because they???re given directives. They show you goals, clips and videos but I don???t think they???re completely sure either.???

Thierry Henry also praised the decision to disallow Casemiro???s second-half strike.

Henry said: ???The referee, Friend, on the line was brave. Sometimes we don???t know why he is there.

???Surely he is there to help the man in the middle, who didn???t see it, so he did that. It was a very good decision.???