Panasonic Wild Knights made it five straight bonus-point wins to start the Japan Rugby Top League season Saturday, beating Toyota Verblitz 43-16 at Kumagaya Sports Stadium.

Robbie Deans' side were made to work hard by Jake White's team, for whom Lionel Cronje and captain Kazuki Himeno were outstanding. But the hosts' depth came to the fore in the second half, when internationals such as Atsushi Sakate and captain Shunsuke Nunomaki came off the bench to join forces with the likes of David Pocock and Daniel Heenan to help Akihito Yamada to a hat-trick of tries.

The win sees the Wild Knights head the White Conference with a maximum 25 points -- just one of three unbeaten teams in the two conferences and the only one not to drop a point.

In the first game of the doubleheader in Kumagaya, defending champions Suntory Sungoliath went back on top of the Red Conference with 24 points after coming from behind to beat Kubota Spears 54-17.

A first-half hat-trick from man-of-the-match Atsushi Hiwasa, after a try by Grant Hattingh had given the Spears the early upper-hand, laid the seeds for Suntory's win.

Wallabies legend Matt Giteau finished the day with six conversions from seven attempts as Suntory went two points above Kobe Kobelco Steelers, who picked up their fifth win on Friday night.

In the day's other games, a second half hat-trick of tries from Amanaki Lotoahea helped Ricoh Black Rams to a 32-5 win over Coca-Cola Red Sparks, for whom Kohei Ishigaki was shown a red card after just seven minutes.

NTT Communications Shining Arcs downed Toyota Industries Shuttles 32-24 for their third victory of the season, while NEC Green Rockets also made it three wins and two losses for the season as they topped Munakata Sanix Blues 29-17.

Keisuke Moriya got the scoreboard ticking over for Panasonic in just the eighth minute as he made the most of a big hole in the Toyota midfield.

Berrick Barnes banged over the conversion and then added a snap drop goal to make it 10-0 before Cronje closed the gap with a 28th-minute penalty.

A scintillating break from Kenki Fukuoka was finished off by Asaeli Ai Valu, but it was offset by a well-constructed score by Himeno -- in his first season of professional rugby -- as the sides went into the break with Panasonic leading 17-10.

The second half started with neither side able to exert their authority until Yamada made the most of a handling error in the 52nd minute to cross for Panasonic's third try.

Cronje closed the gap with a second penalty three minutes later before Yamada crossed twice in the space of five minutes to complete his hat-trick.

The flying wing's second try of the evening came when he followed up a superb grubber kick from Nunomaki, whose vision and skill reminded everyone why he was a flyhalf and center at school and university before moving into the back row. The third was the result of a good break and quick reactions from Rikiya Matsuda.

Barnes added the extras to both five-pointers from out wide before his replacement Takuya Yamasawa added icing to the cake with a solo try three minutes from time that he duly converted to complete the scoring.