Complex sentence: It was the final game of the 1980--81 European Cup Winners'Cup, and the 21st European Cup Winners' Cup Final, held at Rheinstadion in Düsseldorf, West Germany.
Split into simpler sentences: It was the final match of the 1980--81 European Cup Winners'Cup and the 21st European Cup Winners' Cup Final. The final was held at Rheinstadion in Düsseldorf, West Germany.