| ITF M25 Trnava | 11/29 13:10 | 25 | Marek Gengel v Jakub Kroslak | 3-6,7-6,6-3 | |
| ITF M25 Sharm El Sheikh | 11/20 08:00 | 29 | Amr Elsayed v Marek Gengel | 3-6,1-6 | |
| ITF M25 Sharm El Sheikh | 11/19 08:00 | 28 | Marek Gengel v Karim-Mohamed Maamoun | 7-5,7-6 | |
| ITF M25 Sharm El Sheikh | 11/18 08:00 | 27 | Yeongseok Jeong v Marek Gengel | 3-6,2-6 | |
| ITF M25 Sharm El Sheikh | 11/17 08:00 | 26 | Michal Novansky v Marek Gengel | 3-6,1-6 | |
| ITF M25 Sharm El Sheikh | 11/16 08:00 | 25 | Sebastian Sorger v Marek Gengel | 6-7,6-7 | |
| Challenger Sydney | 11/05 00:00 | 28 | [377] Marek Gengel v Marc Polmans [478] | 3-6,4-6 | |
| Challenger Sydney | 11/04 01:50 | 27 | [377] Marek Gengel v Adam Walton [465] | 6-2,6-0 | |
| Challenger Sydney | 11/02 01:25 | 26 | [202] Rio Noguchi v Marek Gengel [377] | 6-7,3-6 | |
| Challenger Sydney | 10/31 05:25 | 25 | [490] Jeremy Beale v Marek Gengel [377] | 4-6,0-6 | |
| Challenger Playford | 10/26 23:30 | 26 | [380] Marek Gengel v James Duckworth [114] | 1-6,2-6 | |
| Challenger Playford | 10/25 03:00 | 25 | Marek Gengel v Alex Bolt | 3-6,6-4,7-6 | |
| Challenger Busan | 10/20 02:00 | 26 | [135] John Millman v Marek Gengel [384] | 6-3,6-3 | |
| Challenger Busan | 10/18 06:55 | 25 | [384] Marek Gengel v Hiroki Moriya [213] | 1-6,6-4,6-2 | |
| Challenger Busan | 10/17 02:00 | 19 | [379] Marek Gengel v Shintaro Mochizuki [407] | 2-6,6-2,0-6 | |
| Challenger Busan | 10/16 01:30 | 14 | Marek Gengel v Jiho Lee | 6-3,6-2 | |
| Challenger Soul | 10/09 04:00 | 14 | [401] Shintaro Mochizuki v Marek Gengel [370] | 6-2,6-3 | |
| Challenger Kwangdžu | 10/04 05:10 | 25 | [161] Maximilian Marterer v Marek Gengel [370] | 6-3,3-6,7-5 | |
| ATP Tel Aviv | 09/25 12:40 | 14 | [153] Alexander Shevchenko v Marek Gengel [380] | 6-4,6-4 | |
| ATP San Diego | 09/18 21:45 | 19 | [127] Facundo Mena v Marek Gengel [388] | 6-3,6-4 | |
| ATP San Diego | 09/17 22:20 | 14 | [388] Marek Gengel v Sebastian Fanselow [281] | 6-2,3-6,6-0 | |
| Challenger Istanbul | 09/13 07:00 | 25 | [388] Marek Gengel v Illya Marchenko [310] | 5-7,4-6 | |
| Challenger Istanbul | 09/12 09:00 | 19 | [382] Marek Gengel v Alexandru Jecan [286] | 6-2,6-0 | |
| Challenger Istanbul | 09/11 07:00 | 14 | [382] Marek Gengel v Fernando Romboli [113] | 6-0,6-1 | |
| Challenger Cassis | 09/05 10:40 | 19 | [87] Albano Olivetti v Marek Gengel [382] | 6-1,6-7,7-6 | |
| Challenger Cassis | 09/04 11:30 | 14 | Saba Purtseladze v Marek Gengel | 5-7,0-6 | |
| Challenger Mallorca | 08/31 14:00 | 25 | [382] Marek Gengel v Altug Celikbilek [231] | 3-6,4-6 | |
| Challenger Mallorca | 08/30 10:30 | 19 | [298] Lukáš Rosol v Marek Gengel [382] | 6-0,6-7,2-6 | |
| Challenger Mallorca | 08/29 09:35 | 14 | [423] Daniel Little v Marek Gengel [382] | 3-6,5-7 | |
| Challenger Praha | 08/25 08:00 | 26 | [415] Martin Cuevas v Marek Gengel [393] | 6-0,6-1 |
Marek Gengel (* 17. září 1995 Rakovník) je český profesionální tenista. Ve své dosavadní kariéře na okruhu ATP World Tour nevyhrál žádný turnaj. Na challengerech ATP a okruhu ITF získal do května 2023 osm titulů ve dvouhře a deset ve čtyřhře.
Na žebříčku ATP byl ve dvouhře nejvýše klasifikován v lednu 2023 na 256. místě a ve čtyřhře pak v březnu 2023 na 148. místě.