Ryo Noguchi and Makoto Hondama won the men and women's All Japan Tennis Championships, a test event for next year's Olympic Games in Tokyo.
With an all-Japanese field competing, Noguchi triumphed in the men's event after defeating compatriot Kita Shimizu 6-3, 6-4 at Ariake Tennis Park.
The women's title went to Hondoma after she came back from a set down to win 4-6, 6-1, 6-1 against Fumiho Akita.
Tokito Niki was victorious in the men's doubles competition for the third time in his career, partnering with Shintaro Imai to beat Keita Shimizu and Shinji Hazawa 7-6, 7-6.
Kanasaki Morisaki and Mitsuharu Yonehara earned the title in the women's doubles after overcoming Haruka Kaji and Junri Waveform 6-4, 6-4.
The competition was a chance for Tokyo 2020 organisers to test the facilities and procedures at the venue before the Games next year.
During a venue tour at the Tokyo 2020 World Press Briefing last month, it was revealed that work on court two, the Park's third showpiece arena, has not started yet, with organisers confirming plans are on schedule for a March 2020 completion.
The Ariake Colosseum is expected to home 10,000 spectators, with a retractable roof giving organisers an extra method to shelter fans from extreme temperatures, should the heatwave from July be repeated in nine months.
Kris Dent, the Internationl Tennis Federation's senior executive director of professional tennis, was among those to have visited the venue during the event and revealed they had assessed many areas.
He described the centre court as "looking fantastic" and generally praised the progress made so far.