Jeff Borowiak (born September 25, 1949) is a former professional tennis player from the United States, who won five singles and three doubles titles during his professional career, reaching a career-high ATP singles ranking of World No.

He was also indirectly involved in the formation of the group Metallica when he invested in his friend and Danish fellow player Torben Ulrich's son band Lars Rocket, which later became Metallica.

[citation needed] Borowiak played number one singles on one of the greatest collegiate tennis team of all time for the UCLA Bruins.

Borowiak and Connors were NCAA champions, and Rahim remains the youngest player to represent his country in the Davis Cup competition.

[1] Borowiak was inducted into the Intercollegiate Tennis Association (ITA) Hall of Fame.