Japan claimed a 33-21 win over Romania in their first Test of their June campaign at Egao Kenko Stadium, Kumamoto on Saturday.
Tries from Akihito Yamada, Kenki Fukuoka and Michael Leitch saw them to the success, with Jumpei Ogura kicking 18 points from the tee.
In reply Mihai Macovei scored twice for Romania in defeat.
Japan led 23-9 at the interval after an impressive 40 minutes that saw them cross twice while limiting the Romanians to only penalty goals.
Vlaicu added two penalties to make it 0-6 but the Brave Blossoms hit back with scores from Yamada and Fukuoka with Ogura kicking well.
The first score of the second-half was always going to be crucial and it went the way of the home side when Leitch crossed two minutes in. That made it 30-9 with the extras to leave Romania a mountain to climb as changes began to be made from both head coaches in Kumamoto.
Romania would strike next though through captain Macovei and with Heiichiro Ito yellow carded on 63 minutes, the visitors sensed a chance.
Macovei scored again on 66 minutes and with Vlaicu's conversion the Romanians were now just 33-21 behind, setting up an intriguing finish.
But Japan would hold on to start their June Test campaign on a positive note.
Tries: Yamada, Fukuoka, Leitch
Cons: Ogura 3
Pens: Ogura 4
Yellow Card: Ito
Tries: Macovei 2
Pens: Vlaicu 3
Japan: 15 Ryuji Noguchi, 14 Akihito Yamada, 13 Timothy Lafaele, 12 Derek Carpenter, 11 Kenki Fukuoka, 10 Jumpei Ogura, 9 Fumiaka Tanaka, 8 Amanaki Mafi, 7 Yoshitaka Tokunaga, 6 Michael Leitch, 5 Uwe Helu, 4 Kotaro Yatabe, 3 Takuma Ashara, 2 Shota Horie (c), 1 Koki Yamamoto
Replacements: 16 Yusuke Niwai, 17 Keita Inagaki, 18 Heiichiro Ito, 19 Yuya Odo, 20 Hendrik Tui, 21 Keisuke Uchida, 22 Yu Tamura, 23 Kotaro Matsushima
Romania: 15 Sabin Stratila, 14 Fonovai Tangimana, 13 Paula Kinikinilau, 12 Sione Fakaosilea, 11 Jack Cobden, 10 Florin Vlaicu, 9 Florin Surugiu, 8 Mihai Macovei (c), 7 Viorel Lucaci, 6 Andrei Gorcioaia, 5 Marius Antonescu, 4 Johannes Van Heerden, 3 Andrei Ursache, 2 Otar Turashvili, 1 Ionel Badiu
Replacements: 16 Andrei Radoi, 17 Constantin Pristavita, 18 Alexandru Tarus, 19 Valentin Poparlan, 20 Vlad Nistor, 21 Tudorel Bratu, 22 Luke Samoa, 23 Ionut Dumitru
Referee: Alex Ruiz (France)
Assistant Referees: JP Doyle (England), Will Houston (Australia)
TMO: Glenn Newman (New Zealand)