Mariusz Fyrstenberg
Mariusz Stanisław Fyrstenberg is a retired Polish tennis player who was a doubles specialist.
Fyrstenberg primarily partnered Marcin Matkowski. The pair won the Madrid Open twice, in addition to reaching the final at the US Open. They also reached the final of the ATP Finals and participated six times at the event overall. Fyrstenberg won 18 doubles title in his career and achieved a highest ranking in doubles of world No. 6 in August 2012.
He is currently the coach of Jan Zieliński and Hugo Nys.
ATP career finals
Doubles: 44 (18 titles, 26 runner-ups)
| Result | W–L | Date | Tournament | Tier | Surface | Partner | Opponents | Score |
| Win | 1–0 | 2003 [Idea Prokom Open – Men's doubles|] | Sopot Open, Poland | International | Clay |  |