Tanaka (29), the Japanese international who has played for Otago for the past two seasons and is about to enter his second season with the Highlanders, has already won a title this year and the season has not even started.
Tanaka won the Japan Top League title on Tuesday when his Panasonic Wild Knights beat Suntory 45-22 in the final.
Tanaka played a starring role, and reports said he outplayed Springbok halfback Fourie du Preez.
The match was to be played on Sunday but was delayed by two days because of snow in Tokyo.
Tanaka had flown home just over two weeks ago to play in the semifinal of the competition.
He then came back to New Zealand and flew
to Nelson last Friday to play the second half in the match between the Highlanders and the Crusaders.
On Saturday morning, he flew from Nelson to Auckland and then on to Tokyo to be available for the final.
He was due back in Dunedin today but would not travel to Sydney to play the Waratahs as the Highlanders leave today.
Tanaka's wife and their baby, born in October last year, will move to Dunedin next month.
It was a touch-and-go victory for Tanaka and his side, which trailed 19-16 at halftime.
But it pulled away in the second half, with former Wallaby Berrick Barnes landing eight penalties in the match.
Aki Yamada, who played briefly for University A last year in the Dunedin club competition, scored two tries for Panasonic, and was named most valuable player in the finals series.