 In his time at Manchester United, he was selected to represent Denmark at the 1986 World Cup, where he played two of Denmark's four games before elimination.In 1987, Sivebæk was told he would not be a first team regular at Manchester United, and he moved to French club AS Saint-Étienne.While at Saint-Étienne, he was selected for the 1988 European Championship, where he played two of Denmark's three games.