By Adriana Garcia MADRID (Reuters) - Atletico Madrid will try to secure their first win at the Nou Camp since 2006 when they face Barcelona on Wednesday in a heavyweight clash between La Liga title contenders. Real Madrid, who are chasing history in their home game against Villarreal the same day, head the standings by three points from Barca after four rounds of matches. Atletico have enjoyed success against Barcelona at home and especially in the Champions League, knocking them out in the 2013-14 quarter-finals and again last season. More...