The Cheetahs did enough to secure a 38-31 win over a spirited Sunwolves team in Bloemfontein on Saturday.
The yellow-carding of Takuma Asahara proved costly for the Japanese as they pushed the South Africans all the way.
The replacement prop was sin-binned after 65 minutes for a second offence in quick succession with the visitors clinging to a 31-30 lead at Free State Stadium in Bloemfontein.
Cheetahs opted for a scrum from the resultant penalty and scrumhalf Tian Meyer threw a long pass to send centre Rayno Benjamin over in the corner.
Flyhalf Fred Zeilinga failed to convert, but added a penalty while the Sunwolves were still a man short to close the scoring.
Sunwolves, who lost 17-92 at the same ground last year, finished the match in the Cheetahs half and were let down by a couple of unforced errors.
They allowed the South Africans to steal a line-out and a knock-on by lock Liaka Moli halted a promising multi-phase attack.
Running the Cheetahs so close must encourage a team humiliated 17-83 in Tokyo two weeks ago by title-holders Hurricanes of New Zealand.
Sunwolves also lost to another South African side, Southern Kings, in Singapore last weekend.
It was the third consecutive home fixure for the Cheetahs, who began with a loss to the Lions, then beat Bulls in a second South African derby.
Sunwolves were ahead within 30 seconds of the kick-off thanks to a try by ful-back Shota Emi and trailed only 17-20 at half-time.
A try by centre Clinton Swart put the hosts 13 points ahead early in the second half before a brace from wing Kenki Fukuoka gave the Sunwolves a one-point advantage.
Asahara was then yellow-carded and the match swung decisively in favour of the home side.
Skipper and hooker Torsten van Jaarsveld, flank Teboho Mohoje, Swart and Benjamin scored tries for the Cheetahs.
Zeilinga missed only one shot at goal as he kicked three conversions and four penalties.
Fukuoka (2), Emi and New Zealand-born flyhalf Hayden Cripps crossed for Sunwolves tries.
Cripps kicked two conversions and a penalty and his replacement and fellow New Zealander, Jamie-Jerry Taulagi, slotted two conversions.
Man of the match: Sunwolves No.13 William Tupou was immense in the midfield. However, the award goes to wing Kenki Fukuoka for running the Cheetahs ragged and scoring four tries.
Tries: Van Jaarsveld, Mohoje, Swart, Benjamin
Cons: Zeilinga 3
Pens: Zeilinga 4
Tries: Emi, Cripps, Fukuoko 2
Cons: Cripps 2, Taulagi 2
Yellow card: Takuma Asahara (Sunwolves, 64 - cynical play, not rolling away)
Cheetahs: 15 Clayton Blommetjies, 14 Zee Mkhabela, 13 Ryno Benjamin, 12 Clinton Swart, 11 Raymond Rhule, 10 Fred Zeilinga, 9 Tian Meyer, 8 Neill Jordaan, 7 Teboho Mohoje, 6 Paul Schoeman, 5 Francois Uys, 4 Justin Basson, 3 Johan Coetzee, 2 Torsten van Jaarsveld (captain) , 1 Charles Marais.
Replacements: 16 Danie Mienie, 17 Elandre Huggett, 18 Tom Botha, 19 Armandt Koster, 20 Henco Venter, 21 Niel Marais, 22 Ali Mgijima, 23 Ruan van Rensburg.
Sunwolves: 15 Shota Emi, 14 Takaaki Nakazuru, 13 William Tupou, 12 Derek Carpenter, 11 Kenki Fukuoka, 10 Hayden Cripps, 9 Keisuke Uchida, 8 Willem Britz, 7 Shuhei Matsuhashi, 6 Edward Quirk, 5 Uwe Helu, 4 Liaki Moli, 3 Yasuo Yamaji, 2 Yusuke Niwai, 1 Koki Yamamoto.
Replacements: 16 Atsushi Sakate, 17 Masataka Mikami, 18 Takuma Asahara, 19 Sam Wykes, 20 Shokei Kin, 21 Kaito Shigeno, 22 Jumpei Ogura, 23 Jamie-Jerry Taulagi.
Referee: Rasta Rasivhenge (South Africa)
Assistant referees: Jaco Peyper (South Africa), Quinton Immelman (South Africa)
TMO: Johan Greeff (South Africa)
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