is a Japanese tennis player.

Niki has a career high ATP singles ranking of No. 278 achieved on 23 March 2015 and a career high ATP doubles ranking of No. 269 achieved on 23 April 2018.

Niki made his ATP main draw debut at the 2015 ATP Shenzhen Open where he qualified for the main draw. He lost to Bai Yan in the first round.

He has reached 22 singles finals to date, posting a record of 10 wins and 12 losses. Additionally, he has reached 57 doubles finals, holding a record of 26 wins and 31 losses. All of his career finals in both single and doubles have come on the ITF Futures Tour with the exception of 1, where he and partner Yuichi Ito lost in the final of the ATP Challenger tournament in Granby Canada.

ATP Challenger and ITF Futures finals

Singles: 22 (10–12) LegendATP Challenger (0–0)ITF Futures (10–12)Finals by surfaceHard (8–11)Clay (1–1)Grass (1–0)Carpet (0–0)

ResultW–LDateTournamentTierSurfaceOpponentScoreLoss0–1Kazakhstan F2, TarazFuturesHard Federico Gaio6–0, 4–6, 2–6Win1–1Japan F7, TokyoFuturesGrass Hiroki Kondo6–2, 6–4Loss1–2Japan F2, TokyoFuturesHard Chang Yu2–6, 3–6Loss1–3Israel F7, AshkelonFuturesHard Enzo Couacoud5–7, 1–6Loss1–4Japan F1, NishitamaFuturesHard Wu Di2–6, 4–6Win2–4Japan F3, KofuFuturesHard Yusuke Watanuki6–4, 6–2Loss2–5Japan F4, TsukubaFuturesHard Masato Shiga6–3, 6–7(4–7), 3–6Win3–5Guam F1, TumonFuturesHard Jeevan Nedunchezhiyan6–7(6–8), 6–2, 7–5Win4–5Japan F5, KaruizawaFuturesClay Yuya Kibi6–4, 3–6, 6–1Win5–5Japan F1, NishitamaFuturesHard Yuya Kibi6–3, ret.Win6–5Japan F2, TokyoFuturesHard Shintaro Imai6–7(4–7), 6–4, 6–2Loss6–6Japan F4, TsukubaFuturesHard Yasutaka Uchiyama1–6, 2–6Win7–6Chinese Taipei F1, KaohsiungFuturesHard Lee Kuan-Yi6–4, 6–4Win8–6Chinese Taipei F2, KaohsiungFuturesHard Jumpei Yamasaki4–6, 7–5, 6–3Loss8–7Hong Kong F6FuturesHard Bai Yan1–6, 4–6Loss8–8Japan F1. NishitamaFuturesHard Yusuke Takahashi5–7, 3–6Win9–8Japan F3. KofuFuturesHard Shane Vinsant6–4, 4–0 ret.Loss9–9Japan F4. TsukubaFuturesHard Yusuke Takahashi2–6, 2–6Loss9–10Singapore F2, SingaporeFuturesHard Collin Altamirano6–7(5–7), 3–6Loss9–11Austria F5, VogauFuturesClay Matias Zukas3–6, 3–6Win10–11USA F26, Fountain ValleyFuturesHard Michael Shabaz6–3, 3–6, 6–3Loss10–12M25 Matsuyama, JapanWorld Tennis TourHard Shuichi Sekiguchi4–6, 4–6

Doubles: 57 (26–31) LegendATP Challenger (0–1)ITF Futures (26–30)Finals by surfaceHard (23–24)Clay (3–7)Grass (0–0)Carpet (0–0)

ResultW–LDateTournamentTierSurfacePartnerOpponentsScoreLoss0–1Japan F5, KaruizawaFuturesClay Fumiaki Kita Lee Chui-Hee Kwon Oh-Hee5–7, 3–6Win1–1Kazakhstan F3, AlmatyFuturesHard Arata Onozawa Mikhail Fufygin Ilia Starkov1–6, 7–5, [10–7]Loss1–2India F7, DelhiFuturesHard Vitali Reshetnikov Divij Sharan Rohan Gajjar2–6, 6–7(7–9)Loss1–3Serbia F11, NisFuturesClay Stepan Khotulev Gleb Sakharov Mikhail Vasiliev2–6, 6–2, [7-10]Win2–3Serbia F12, Soko BanjaFuturesClay Stepan Khotulev Tomislav Jotovski Stefan Micov7–5, 6–3Loss2–4Chinese Taipei F4, TainanFuturesClay Arata Onozawa Huang Liang-Chi Yi Chu-Huan3–6, 4–6Win3–4Japan F2, TokyoFuturesHard Arata Onozawa Gao Xin Chang Yu3–6, 6–1, [10-6]Loss3–5China F8, FuzhouFuturesHard Arata Onozawa Gao Xin Li Zhe2–6, 3–6Win4–5Japan F5, KaruizawaFuturesClay Shota Tagawa Gengo Kikuchi Yuki Matsuo6–4, 6–4Win5–5Japan F7, SapporoFuturesClay Arata Onozawa Yasutaka Uchiyama Shota Tagawa7–6(7–3), 6–2Loss5–6Granby, CanadaChallengerHard Yuichi Ito Vasek Pospisil Philip Bester1–6, 2–6Loss5–7Israel F8, AshkelonFuturesHard Arata Onozawa Sam Barry Sebastian Lavie6–7(7–9), 6–2, [10–12]Win6–7Israel F9, Ramat HasharonFuturesHard Arata Onozawa Sam Barry Daniel Glancy6–3, 6–4Loss6–8Thailand F1, BangkokFuturesHard Arata Onozawa Sonchat Ratiwatana Sanchai Ratiwatana7–6(8–6), 2–6, [7–10]Loss6–9Guam F1, TumonFuturesHard Yuichi Ito Bumpei Sato Yasutaka Uchiyama6–7(2–7), 4–6Win7–9Chinese Taipei F2, Taipei CityFuturesHard Arata Onozawa Hsieh Cheng-peng Chen I-Ta6–4, 6–4Win8–9Cambodia F2, Phnom PenhFuturesHard Arata Onozawa Toshihide Matsui Danai Udomchoke7–6(12–10), 7–6(10–8)Loss8–10Cambodia F3, Phnom PenhFuturesHard Arata Onozawa Karunuday Singh Ramkumar Ramanathan4–6, 3–6Loss8–11Australia F1, Happy ValleyFuturesHard Yasutaka Uchiyama Marcus Daniell Dane Propoggia3–6, 2–6Win9–11Japan F3, KofuFuturesHard Arata Onozawa Toshihide Matsui Danai Udomchoke6–4, 6–2Win10–11Guam F1, TumonFuturesHard Bumpei Sato Yuya Kibi Tomohiro Masabayashi6–1, 6–3Loss10–12Japan F6, KashiwaFuturesHard Arata Onozawa Yusuke Watanuki Keisuke Watanuki6–7(4–7), 6–4, [7–10]Loss10–13Japan F8, SapporoFuturesClay Arata Onozawa Takao Suzuki Yasutaka Uchiyama2–6, 6–7(4–7)Win11–13Australia F7, CairnsFuturesHard Yuya Kibi Dane Propoggia Brydan Klein1–6, 7–6(7–2), [10–4]Win12–13Japan F1, NishitamaFuturesHard Yuya Kibi Yuichi Ito Arata Onozawa6–3, 3–6, [11–9]Win13–13Japan F4, TsukubaFuturesHard Shintaro Imai Jarryd Chaplin Ben McLachlan6–2, 6–4Win14–13Japan F6, KashiwaFuturesHard Yuya Kibi Lee Duckhee Woo Chung Hyo6–0, 6–3Win15–13Japan F3, KofuFuturesHard Shintaro Imai Yuya Kibi Toshihide Matsui6–1, 6–2Loss15–14Japan F5, KashiwaFuturesHard Shintaro Imai Yuichi Ito Sho Katayama3–6, 3–6Loss15–15Korea F4, GimcheonFuturesHard Shintaro Imai Nam Ji Sung Song Min-Kyu4–6, 4–6Win16–15Hong Kong F6FuturesHard Geoffrey Blancaneaux Karan Rastogi Wong Chun Hun7–6(8–6), 6–0Loss16–16Japan F1, NishitamaFuturesHard Kaito Uesugi Katsuki Nagao Hiromasa Oku0–6, 6–7(2–7)Win17–16Japan F2, TokyoFuturesHard Kaito Uesugi Gengo Kikuchi Shunrou Takeshima7–6(7–5), 6–7(2–7), [10–3]Win18–16Japan F5, KashiwaFuturesHard Shintaro Imai Katsuki Nagao Hiromasa Oku6–4, 6–4Loss18–17Japan F6, KaruizawaFuturesClay Shintaro Imai Toshihide Matsui Christopher Rungkat5–7, 2–6Win19–17Chinese Taipei F1, TaipeiFuturesHard Shintaro Imai Lee Kuan-Yi Liu Shao-Fan7–5, 6–4Loss19–18Chinese Taipei F2, TaipeiFuturesHard Shintaro Imai Yi Chu-Huan Chiu Yu-Hsiang6–2, 6–7(5–7), [8–10]Win20–18Hong Kong F3FuturesHard Shintaro Imai Wong Hong Kit Yeung Pak Long7–5, 6–2Loss20–19Hong Kong F5FuturesHard Corentin Denolly Evan King Michael Zhu4–6, 2–6Loss20–20Hong Kong F6FuturesHard Shintaro Imai Yuto Sakai Yunosuke Tanaka6–2, 3–6, [4–10]Win21–20Japan F1, NishitamaFuturesHard Shintaro Imai Soichiro Moritani Sho Katayama6–1, 6–4Win22–20Japan F2, TokyoFuturesHard Shintaro Imai Lee Tae-Woo Lim Yong-kyu7–5, 6–3Win23–20Japan F6, MatsuyamaFuturesHard Shintaro Imai Yuto Sakai Yuhel Kono6–4, 6–3Loss23–21Singapore F2, SingaporeFuturesHard Shintaro Imai Francis Casey Alcantara Collin Altamirano1–6, 4–6Loss23–22Korea F2, GyeongsanFuturesHard John-Paul Fruttero Nam Ji Sung Lim Yong-kyu4–6, 1–6Loss23–23Austria F5, VogauFuturesClay Yuta Shimizu Alejo Vilaro Matias Zukas3–6, 6–3, [4–10]Loss23–24Netherlands F4, OldenzaalFuturesClay Kazuki Nishiwaki Niels Lootsma Glenn Smits6–3, 5–7, [6–10]Loss23–25Canada F7, TorontoFuturesHard Felix Corwin Francesco Ferrari Michail Pervolarakis3–6, 3–6Win24–25M15 Nishitama, JapanWorld Tennis TourHard Shintaro Imai Wishaya Trongcharoenchaikul Blake Ellis1–6, 7–6(10–8), [10–5]Loss24–26M15 Tokyo, JapanWorld Tennis TourHard Shintaro Imai Nam Ji Sung Song Min-Kyu6–4, 6–7(4–7), [7–10]Loss24–27M15 Daegu, South KoreaWorld Tennis TourHard Issei Okamura Lim Yong-kyu Song Min-Kyu3–6, 5–7Loss24–28M15 Kiryat Shmona, IsraelWorld Tennis TourHard Marat Deviatiarov Federico Bertuccioli Andrea Picchione6–4, 4–6, [12–14]Loss24–29M15 Sharm El Sheikh, EgyptWorld Tennis TourHard Yusuke Takahashi Jacopo Berrettini Neil Oberleitner3–6, 3–6Win25–29M15 Heraklion, GreeceWorld Tennis TourHard Yuki Mochizuki Runhao Hua Ze Zhang6–3, 6–4Loss25–30M25 Idanha-a-Nova, PortugalWorld Tennis TourHard Kaito Uesugi Thomas Fancutt Evan Hoyt3–6, 2–6Loss25–31M15 Chiang Rai, ThailandWorld Tennis TourHard Shinji Hazawa Ji Sung Nam Min Kyu Song1–6, 4–6Win26–31M25 Harmon, GuamWorld Tennis TourHard Takeru Yuzuki Seong Chan Hong Cheong-Eui Kim1–6, 7–6(7–4) [11–9]

External links