In 1928 Cilly Aussem’s mother claimed that Paula von Reznicek had twice beaten her daughter by using hypnotism, which led to a lawsuit in which Von Reznicek filed charges of ‘defamation of character’ and Aussem’s mother charged her with ‘insulting assault.’ She lost her German Championships singles title in 1928 after a three-sets defeat in the final to Daphne Akhurst. Aussem suffered from eye inflammation throughout 1929 but in 1930 she had her breakthrough. With Tilden, she won all the mixed double titles on the Riviera that season. At the French Championships, Aussem and Tilden defeated the world’s top two mixed doubles teams, Elizabeth Ryan / Jean Borotra and Eileen Bennett Whittingstall / Henri Cochet, and took the French title. Aussem also reached a singles semifinal, where she lost to Helen Jacobs. At Wimbledon, Cilly Aussem won against Jacobs in the quarterfinal and faced Ryan in a semifinal. The match ended unexpectedly. While running, Aussem tumbled, fell, twisted her ankle and lost consciousness. After that incident, health problems hampered the remainder of Aussem’s tennis career. Her eyes became more and more sensitive, so that she had to spend hours in a darkened room waiting for her matches to start. In August 1930 she won her second German Championships singles title after a straight-sets victory in the final against compatriot Hilde Krahwinkel. At the end of 1930, three years after starting to play in international championships, she reached second place in the world rankings.

1931 was Cilly Aussem’s most successful year. She won the French Championships, defeating Betty Nuthall of the United Kingdom, and the German Championships after a win in the final against Irmgard Rost. Aussem also won the Wimbledon singles championship, defeating her compatriot Hilde Krahwinkel in the final in straight sets. She became the first German woman to do so. Aussem again was ranked World No. 2 behind Helen Wills Moody. An English newspaper described Aussem as follows: “There is a Paavo Nurmi of tennis from Germany, a beautiful young girl. Her quickness and her fighting spirit are singular!” All seemed to be prepared for a great international career when something happened that stopped Aussem’s rapid rise. Celebrating the successful year of 1931, Aussem and her friend and teammate, Irmgard Rost, decided to travel to Argentina, Brazil and Chile. Aussem won some tournaments there but also caught a serious liver inflammation. Back in Germany, she underwent surgery from which she recovered only very slowly. During the two years she was not allowed to participate in sports, she dreamed about a comeback. In 1933, Cilly Aussem returned to the courts but was not able to regain her form. In 1934, she again reached ninth place in the worldwide rankings but started losing to players she had always beaten. She lost at Wimbledon to Helen Jacobs in a quarterfinal and decided to quit the tour at the young age of 25. In 1963, she underwent another liver surgery, a late consequence of that trip to South America three decades before. Aussem did not recover. She died on 22 March 1963, at the age of 54.