ITF Turkey F11 03/19 07:30 - Di Nicola, Gianluca v Sieber, Marc 6-7,6-7
ITF Turkey F11 03/17 09:00 - Sieber, Marc v Kamil Majchrzak 6-4,6-2
ITF Turkey F7 02/22 09:00 - Sieber, Marc v Dimitar Kuzmanov 5-7,3-6
ITF Turkey F7 02/21 09:00 - Sieber, Marc v Gleb Sakharov Retired
ITF Turkey F7 02/20 09:00 - Stanek, Robin v Sieber, Marc 6-4,4-6,1-6
ITF Turkey F7 02/19 11:10 - Evgeny Karlovskiy v Sieber, Marc 2-6,6-3,4-6
ITF Turkey F7 02/18 10:40 - Sieber, Marc v Vorster, Tucker 6-4,4-6,7-5
ITF Turkey F7 02/17 07:30 - Sieber, Marc v Patael, Ben 6-1,6-3
ITF Turkey F7 02/16 08:00 - Sieber, Marc v Kuerschner, Alexander 6-4,7-5
ITF Turkey F7 02/14 11:00 - Nerman Fatic v Sieber, Marc 3-6,1-6
Turkey F6, Singles Qualifying 02/13 08:00 - Sieber, Marc v Podzus, Martins 3-6,3-6
Turkey F6, Singles Qualifying 02/12 12:10 - Takeuchi, Kento (1987) v Sieber, Marc 2-6,2-6
Turkey F6, Singles Qualifying 02/11 13:45 - Sieber, Marc v Dima, Dragos 2-6,6-2,6-1
Turkey F6, Singles Qualifying 02/09 08:00 - Dmitriev, Kirill v Sieber, Marc 2-6,6-7
Turkey F6, Singles Qualifying 02/08 08:00 - Tagashira, Kento v Sieber, Marc 1-6,1-6
Turkey F6, Singles Qualifying 02/07 07:00 - Hirschmueller, Christian v Sieber, Marc 4-6,0-6
ITF Turkey F38 11/02 10:00 - Sieber, Marc v Mohamed Safwat 5-7,6-3,4-6
ITF Turkey F38 11/01 09:45 - Sieber, Marc v Federico Gaio 6-2,5-7,6-2
ITF Turkey F38 10/31 08:30 - Krstin, Pedja v Sieber, Marc 7-6,4-6,4-6
ITF Turkey F38 10/30 08:00 - Sieber, Marc v Paul Woerner 6-1,6-3
ITF Turkey F38 10/29 09:25 - Sieber, Marc v Simon, Tobias 6-4,6-3
ITF Turkey F38 10/27 07:30 - Gooch, Damon v Sieber, Marc 2-6,6-1,4-6
ITF Turkey F37 10/24 10:50 - Dmitriev, Kirill v Sieber, Marc 7-5,6-4
ITF Turkey F37 10/23 11:00 - Sieber, Marc v Dmitry Popko 6-3,6-3
ITF Turkey F37 10/21 10:15 - Ergeneman, Gokberk v Sieber, Marc 1-6,0-6