The former Gor Mahia striker scored the lone goal in the 24th minute to ensure Kashiwa pick three points in what was their first game of the season.
Olunga was in fine form last season, scoring 27 goals as he guided the club back to the J1 league and he seems to have picked from where he left as he has already scored two goals, the first in a friendly against Jef United on February 8. He hopes to keep on scoring.
“Hopefully first of many goals. Thanks fans for the support, God above all,” he tweeted after the match.
Up next for Reysol is a league match against Consadole Sapporo on Saturday.