Defending Japan Rugby Top League champions Suntory Sungoliath showed they are not giving their title up without a fight Saturday as they came from behind to beat Yamaha Jubilo 27-24 at Prince Chichibu Memorial Rugby Ground.

A try after the hooter from Kosei Ono from a quickly taken penalty by Atsushi Hiwasa saw Keisuke Sawaki's side pick up their third win of the season and ruin the return to Tokyo of Japan's 2015 Rugby World Cup hero Ayumu Goromaru.

"It was always going to be hard," said Ono. "Every team is going to come at us and it's a matter of fronting up and being game smart and being better than them."

Goromaru, who was playing his 100th Top League game, had done his bit for Yamaha, kicking three conversions and a penalty as both he and Ono slotted over every kick that came their way.

But his and his team's day was ruined by a tenacious Suntory side that never gave up.

"I wanted to give something back to the team," rued Goromaru.

"Although we lost I am sure that was a good game to watch and will help develop the level of the Top League."

In the day's other games, Kobe Kobelco Steelers jumped above Suntory on points difference in the Red Conference thanks to a 45-7 win over Kubota Spears. Steelers joined Sungoliath and the White Conference's Panasonic as the league's only unbeaten sides.

Former Springbok Andries Bekker touched down twice for the Steelers, while Codey Rei kicked five conversions and a penalty goal from as many attempts.

NEC Green Rockets picked up their second win of the season as they downed winless Toyota Industries Shuttles 42-26, as did Ricoh Black Rams who beat Munakata Sanix Blues 35-14 and Toyota Verblitz who handed Canon Eagles their third straight loss with a 34-12 drubbing.

Meanwhile, newly promoted NTT Docomo Red Hurricanes picked up their first win of the new campaign and kept Coca-Cola Red Sparks winless thanks to a 28-24 victory in Kagoshima.

In the match-up between last season's champions and runners-up, a compelling first half played in front of 14,054 at Chichibunomiya saw both sides reduced to 14 men at one stage, and Suntory making more of the opportunities that came their way to go into the break leading 17-10.

Shota Emi got the scoreboard ticking over in the 13th minute when he finished off a good break by fellow wing Takaaki Nakazuru and Daishi Murata scored a 70-meter intercept try a minute after the halftime siren sounded.

Kosei Ono added the extras to both five-pointers and also kicked a penalty.

Yamaha, by contrast, spent much of the half camped in the Suntory 22, but managed just a try from Yuki Yatomi for their efforts.

Goromaru, who adjusted his much-copied kicking style while overseas, added the conversion from the touchline and also kicked a penalty to keep the fans happy. But his coach must have been dismayed that Yamaha were not ahead given their territorial advantage.

"We went into the changing room knowing we had had the possession and territory," rued Yamaha center Male Sa'u.

And as Sa'u said they showed "glimpses of what we can do" early in the second half as Chikara Ito crossed the chalk following a good break down the opposite wing by Gerhard van den Heever.

Goromaru nonchalantly slotted the conversion over from the right-hand touchline to bring the teams level again.

A 62nd-minute penalty from Ono, however, saw Suntory regain the upper hand but it lasted just nine minutes as Kyosuke Horie powered over, despite there being more than a hint of a forward pass in the build-up.

Goromaru maintained his 100 percent record with the boot to put four points between the teams and ensure Suntory needed a try to win, which they duly obliged thanks to their tenacity and speed of thought.