See main article: 1991 ATP German Open. The 1991 German Open was a tennis tournament played on outdoor clay courts and was part of the ATP Championship Series of the 1991 ATP Tour.[1] It took place at the Rothenbaum Tennis Center in Hamburg, Germany, from 6 May until 13 May 1991. Sergio Casal and Emilio Sánchez won in the final against Cássio Motta and Danie Visser, 7–6, 7–6.[1]