LONDON: Chelsea striker Diego Costa has avoided disciplinary action after appearing to kick out at Liverpool's Martin Skrtel in Saturday's 3-1 defeat, according to English Football Association sources. Referee Mark Clattenburg is understood to have seen the incident and opted against issuing a caution, meaning there can be no retrospective sanction by the authorities. The two players had fallen to the ground after a challenge by Spanish international Costa. 'I think it is a clear red card,' former World Cup final referee Howard Webb said on television at the time. 'He commits a foul on Martin Skrtel, then there is a little kick. The second action is a clear act of violent conduct. Diego Costa is a lucky boy on that occasion.'