His biggest individual tournament victories in singles were his two Swiss International Championships in 1946 and 1950.

In July 1949, he and Davis Cup team-mate Jaroslav Drobný defected while attending that year's Swiss Championships in Gstaad.

[2][3][4] He continued to tour the amateur tennis circuit thereafter, first with Swiss papers until in 1950 he and Drobny were both granted Egyptian citizenship.

[5] Subsequently Černík was able to settle in the United States, and worked for two years as the head coach of the Tar Heels, the men's tennis programme at the University of North Carolina.

[6] In later life Černík retired to Palm Beach, Florida, where he was the Tennis Professional at the Everglades Club.