14 June 1887|
Frankfurt am Main, German Empire
|Died||3 May 1968
Wiesbaden, West Germany
|Plays||Left-handed (one-handed backhand)|
|Highest ranking||No. 8 (1920, Karoly Mazak)|
|Grand Slam Singles results|
|Olympic Games||Bronze Medal (1912)|
|Grand Slam Doubles results|
|Other doubles tournaments|
|Olympic Games||1R (1908)|
|Grand Slam Mixed Doubles results|
|Wimbledon||2R (1913, 1927)|
|Davis Cup||SF (1913, 1914)|
He played at the 1908 Summer Olympics and at the 1912 Summer Olympics in Stockholm, Sweden where he won a bronze medal in the men's singles tournament. In 1912, he also reached the final at the World Hard Court Championships at Paris which he lost to his compatriot Otto Froitzheim. At Wimbledon, he reached his best result in 1913 where he advanced to the semifinals before being stopped by Stanley Doust.
At the end of July 1914, he and Otto Froitzheim played the semifinal of the International Lawn Tennis Challenge at Pittsburgh against Australasia. When World War I broke out, the president of the local tennis club kept this from Froitzheim and Kreuzer as he didn't want to disrupt the match. The German team lost 0–5. On their way back to Germany, their Italian steamboat America was halted off Gibraltar by a British warship and they were placed in a prison in Gibraltar for several months before being sent to detention camps in England. While Kreuzer stayed at a camp near Leeds, officer Froitzheim was kept at Donnington Hall until the end of the war in 1918.
In 1920 he won the International German Championships at the Rothenbaum club in Hamburg, defeating Louis Maria Heyden in the final in three straight sets. He was ranked World No. 8 for 1920 by Karoly Mazak.
- Kaiser, Ulrich. "Der zweite Mann". 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. 78–79. ISBN 3-428-10846-9.
- Mazak, Karoly (2010). The Concise History of Tennis, p. 48.
- "Oscar Kreuzer Olympic Results". sports-reference.com. Retrieved 2013-05-13.
- "Friotzheim, Tennis Star, is Heard From". The Pittsburgh Press. 16 January 1916.
- "Tennis Men Interned" (PDF). The New York Times. 14 February 1915.
- Gillmeister, Heiner. "Kleine und große Geschichte – Davis Cup". 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. 53–54. ISBN 3-428-10846-9.