Union Berlin faces a serious relegation threat after suffering a heavy defeat against Werder Bremen as Andras Schäfer received an early red card.German authorities are simultaneously investigating a masked supporter who sabotaged a Video Assistant Referee monitor during a match in Münster.Fans displayed banners protesting the technology while referee Felix Bickel awarded a penalty to Hertha Berlin after consulting remote officials.The German Football Association is also considering disciplinary action against an announcer in Cologne for making biased remarks during a game.