Former Premier League referee Howard Webb has labelled Manchester United midfielder Marouane Fellaini "a thug" after the Belgian was caught up in another elbowing storm.

Fellaini swung an arm at Liverpool defender Dejan Lovren in the second leg of their Europa League last-16 tie, won 3-1 on aggregate by the Merseyside team.

A similar incident involving Emre Can in the first leg went unpunished and Webb, who refereed the 2010 World Cup final and later served as the technical director of Professional Game Match Officials Limited, has seen enough.