Shane Williams may be counting down the games until his retirement but he showed Monday he still knows where the try line is.

The 37-year-old Welsh legend, who will hang his boots up at the end of the season, scored within minutes of coming on as a second-half replacement as Mitsubishi DynaBoars beat Kyuden Voltex 36-23 in the opening round of Top Challenge One.

"I managed to hobble my way over in the end," Williams told Kyodo News after the game at Prince Chichibu Memorial Rugby Ground.

The playoff tournament sees the three regional league winners and the top runnerup play each other. The winner is automatically promoted to replace Munakata Sanix Blues in the Top League while the three other teams get one more shot at the big time via one-off games with the sides finishing 13th to 15th in the top flight.

Joining Williams on the scoresheet for the DynaBoars was New Zealand's Rugby World Cup hero Stephen Donald, who touched down once and kicked three conversions and a penalty goal as the Top East champion downed the top side from Kyushu.

In the earlier game Top West champion Honda Heat were far too strong for Kamaishi Seawaves (Top East runnersup), running in nine tries in a 59-0 drubbing, the opening effort going to All Black Hosea Gear.

The series continues Jan. 18 in Osaka with Mitsubishi taking on Honda in a game that will likely determine the series winner and Kyuden playing Kamaishi.

"We've sort of known from the start of the season that it would be between us and Honda and have been keeping an eye on them," said Williams, who played 87 tests for Wales and four for the British and Irish Lions. "We saw today what they are capable of. They look like a Top League side but I think we are more than capable of causing an upset."