Mariusz Stanisław Fyrstenberg is a retired Polish tennis player who was a doubles specialist.

Marcin Matkowski is a Polish former professional tennis player whose speciality is in doubles. He played college tennis at UCLA, where Jean-Julien Rojer was one of his teammates. Matkowski and Mariusz Fyrstenberg won the Madrid Open twice, in addition to reaching the final at the US Open. The duo also reached the final of the ATP Finals and participated six times at the event overall.