Wirth started the 2011 season as the first choice goalkeeper of Unión for the Copa Libertadores preliminary stage against Bolívar, following of the departures of Luis Marín to O'Higgins and Gregory Saavedra to Deportes Temuco. He kept two clean sheets in the two games of the key against Bolívar, helping to his team in advance to the next stage, after a 1–0 win of Unión in the aggregate result. For the national tournament he started in the first week against Cobreloa, in where he conceded two goals in a 2–0 home loss, but in his next game for the second week against Santiago Wanderers, he was the man-of-the-match in a 2–1 victory. Following the incorporation of the keepers Eduardo Lobos and the Uruguayan Federico Elduayen, he was relegated as the second-choice goalkeeper of the club, because Elduayen suffered a serious injury of three-months that forced him to miss the Apertura Tournament.