Former Wallabies' coach Dave Rennie has watched his Kobe Steelers side fall to their second defeat in three matches to open the Japan rugby season as they lost 32-26 against Brave Lupus in Tokyo.

The defending Japan Rugby League One champions were already ahead, leading 20-12 in Sunday's clash, when Kobe prop Kauvaka Kaivelata was sent off for illegal contact.

Brave Lupus winger Jone Naikabula extended the lead with the first of his two second-half tries soon after, and while Rennie's men scored twice in the final five minutes, it came too late to salvage the result.

Todd Blackadder's Brave Lupus are one of three sides to remain unbeaten after three weekends, but Mie Heat lost their perfect record earlier on Sunday when beaten 32-27 by Spears Funabashi Tokyo-Bay.

Both sides scored four tries in a free-flowing contest, with 12 points from the boot of ex-Wallably flyhalf Bernard Foley proving the difference as the 2023 champions claimed their second win of the season.

Rennie's fellow former Australia coach Robbie Deans had a better day on Saturday as his Saitama Wild Knights side secured their third win to top the table, overpowering Black Rams Tokyo in the final quarter to prevail 39-16 after their game opponents had trailed by just four with 25 minutes left.

Shizuoka Blue Revs are the third unbeaten side following a madcap 40-34 win over Sagamihara Dynaboars, which saw the Wellington-schooled Brave Blossoms winger MaloTuitama score three tries for the second week in a row.

Tuitama had also scored three tries in the corresponding match against the Dynaboars last term, while hooker and teammate Takeshi Hino scored twice in each game.

Israel Folau's Urayasu D-Rocks remain winless after falling 40-12 to Yokohama Eagles, while Tokyo Sungoliath and Verbitz played out an entertaining 30-30 draw.

Despite bringing in long-time coaching partner Ian Foster to assist, ex-All Blacks coach Steve Hansen has endured his worst start to a season in six years of coaching in Japan as his 10th-placed Verblitz have yet to win over the opening three weekends.