|Country (sports)|| German Reich (1926–1933)
Nazi Germany (1933–1945)
West Germany (1945–1957)
31 March 1910|
Nuremberg, German Empire
|Died||28 June 1991
|Height||1.70 m (5 ft 7 in)|
|Plays||Right-handed (one-handed backhand)|
|Int. Tennis HoF||2006 (member page)|
|Highest ranking||No. 1 (Pro, 1933, Ray Bowers)|
|US Pro||W (1934)|
|Wembley Pro||W (1937, 1938)|
|French Pro||W (1937, 1938)|
Hans "Hanne" Nüsslein (German pronunciation: ['hans ˈnʏslaɪ̯n]; 31 March 1910 – 28 June 1991) was a German tennis player and coach and former World professional number 1 tennis player who won five professional Majors singles titles during his career.
Nüsslein was born in Nuremberg on 31 March 1910. In his youth, he played football, handball and tennis at the 1. FC Nürnberg. After finishing school he apprenticed as a mechanic. At age 16, he gave tennis lessons to other club members for which he was paid a small amount. After a member of a neighboring club reported this to the German Tennis Federation, Nüsslein received a lifetime ban from amateur competition, preventing him from competing at Grand Slam tournaments. 
Nüsslein then decided to work as a professional tennis coach. On 1 April 1928, he passed the qualifying examination and became a member of the German federation of tennis coaches. He then was hired by the Deutsche Bank in order to give lessons to their executives.
Beside his coaching work, Nüsslein pursued a career on the emerging professional tennis tournaments. In 1929, he reached third place at the German tennis coaches championships. In 1930, he placed second and also won his first international pro tournament: Beaulieu-sur-Mer on the French Riviera.
In 1931, Nüsslein won the German Pro Championships final over Roman Najuch, who previously had won this title 11 consecutive times.That same year, he played tennis legend Bill Tilden in Europe, taking him to 5 sets. Tilden who had never heard of Nüsslein before the match ("Who is Nusslein?") was surprised by the German's performance and invited him to play in his United States pro tour.
In 1933, Nüsslein and Tilden met again in the final of the World Pro Championships. In front of an audience of 7,000, Nüsslein beat Tilden 1–6, 6–4, 7–5 and 6–3. Nüsslein repeated in 1935 over Henri Cochet) and in 1937 over Tilden once more.  Ray Bowers ranked Nüsslein the World No. 1 professional for 1933. On tour in the United States in 1934, Nüsslein won the US Pro title. In 1937 and 1938, he won both the Wembley Pro and the French Pro championships. Another significant professional tournament of the time was the International Pro Championship of Britain, which Nüsslein won for 4 straight years from 1936 to 1939. He was known for his fine groundstrokes. Tennis historian Robert Geist described his playing style: "He possessed classic strokes, equal to Hall of Famers René Lacoste, Henri Cochet, and Karel Koželuh, as well as excellent volleys, magnificent drop shots and breath-taking half-volleys. As consistent as Ken Rosewall, Nüsslein was one of the best players during the 1930s."
From 1936 onwards, Nüsslein focused on coaching. He signed a contract with Rot-Weiss tennis club in Cologne. In the late thirties, Nüsslein coached the first Grand Slam winner Don Budge, the Australian Davis Cup team as well as several German players.
In World War II Nüsslein served in the German army. Towards the end of the war, he suffered an arm injury which affected his tennis. At the 1953 Wembley Pro Championships, age 43, he won eight games against a 25-year-old Pancho Gonzales, losing 4–6, 4–6. In 1954, he won the international tennis coaches championships at Bad Ems. He continued to play tournaments until 1957  and gave tennis lessons until an age of 70. His most prominent tennis pupils included Wilhelm Bungert, Christian Kuhnke, Dieter Ecklebe and Wolfgang Stuck.
Pro Slam tournaments
Singles: 11 (6/5)
|Winner||1933||World Pro||Clay||Bill Tilden||1–6, 6–4, 7–5, 6–3|
|Runner-up||1933||U.S. Pro||Clay||Karel Koželuh||2–6, 3–6, 5–7|
|Runner-up||1934||Wembley Pro||Indoor||Ellsworth Vines||6–4, 5–7, 3–6, 6–8|
|Winner||1934||U.S. Pro||Clay||Karel Koželuh||6–4, 6–2, 1–6, 7–5|
|Runner-up||1935||French Pro||Clay||Ellsworth Vines||8–10, 4–6, 6–3, 1–6|
|Runner-up||1936||Wembley Pro||Indoor||Ellsworth Vines||4–6, 4–6, 2–6|
|Winner||1937||French Pro||Clay||Henri Cochet||6–2, 8–6, 6–3|
|Winner||1937||Wembley Pro||Indoor||Bill Tilden||6–3, 3–6, 6–3, 2–6, 6–2|
|Winner||1938||French Pro||Clay||Bill Tilden||6–0, 6–1, 6–2|
|Winner||1938||Wembley Pro||Indoor||Bill Tilden||7–5, 3–6, 6–3, 3–6, 6–2|
|Runner-up||1939||Wembley Pro||Indoor||Don Budge||11–13, 6–2, 4–6|
- Bowers, Ray. History of the Pro Tennis Wars, Chapter IV: Tilden and Nusslein, 1932-1933, Tennis Server: Between the Lines.
- Collins, Bud (2010). The Bud Collins History of Tennis (2nd ed.). New York: New Chapter Press. p. 621. ISBN 9780942257700.
- Deike, Reiner (2002). "Der verfemte Weltmeister". In Deutscher Tennis Bund. Tennis in Deutschland. Von den Anfängen bis 2002. [Tennis in Germany. From the beginnings to 2002] (in German). Berlin: Duncker & Humblot. pp. 103–104. ISBN 3-428-10846-9.
- McCauley, Joe (2000). The History of Professional Tennis. Windsor: The Short Run Book Company Limited. p. 200.