Saitama Wild Knights kicked off their Japan Rugby League One title defense Saturday with a gritty 22-19 comeback win over Brave Lupus Tokyo.

With multiple players from both teams bidding for World Cup selection, the clash at Saitama's Kumagaya Rugby Stadium lived up to its billing as the most anticipated opening-round match of League One's second season.

Rikiya Matsuda of Saitama Wild Knights scores a try during the second half of a season-opening Japan Rugby League One match against Brave Lupus Tokyo on Dec. 17, 2022, at Kumagaya Rugby Stadium in Saitama Prefecture, eastern Japan. (Kyodo)

The inaugural edition of Japan's rebranded professional rugby union competition wrapped up at Tokyo's National Stadium seven months ago with the Robbie Deans-coached Wild Knights lifting the trophy following their victory over Tokyo Sungoliath.

The champions started the new season on the back foot, however, against a hard-running Brave Lupus outfit coached by former All Black Todd Blackadder.

Two penalties and a converted Michael Leitch try gave the visitors a 13-0 lead before Wild Knights got on the board via Shunsuke Nunomaki's five-pointer.

Brave Lupus flyhalf Tom Taylor slotted his third penalty of the half for a 16-7 27th-minute lead before the momentum began shifting to Deans' star-studded Saitama side.

Japan captain Atsushi Sakate crossed for the hosts on the stroke of halftime, sending them into the break trailing 12-16. Rikiya Matsuda broke the line to run in Saitama's third try, then kicked the extras for a 19-16 lead in the 56th minute.

Taylor brought Brave Lupus level from the kicking tee, but a 71st minute penalty from replacement kicker Takuya Yamasawa clinched the victory for the men in blue.

"There were things we weren't able to do, but I want to take the positives from winning the opening game of the season," Sakate said.

"We hope to win the championship this season, but I also want all of us to get stronger and execute the things we've practiced, one game at a time."

In Saturday's other matches, the promoted Sagamihara Dynaboars overran Black Rams Tokyo 34-8, while Toyota Verblitz were 31-26 winners against Shizuoka Blue Revs.

South Africa scrumhalf Faf de Klerk, who starred for the Springboks during their victorious 2019 World Cup campaign in Japan, may make his League One debut for Yokohama Eagles if he comes off the bench at home Sunday against Kobe Steelers.