The visitors were the first to hit the back of the net through George Mutimba's 31-minute strike before ChrispinOduor and Francis Ouma ensured the 'Slum Boys' bag maximum points.
Kimanzi was left with sweet words on his lips for his charges after that outstanding comeback.
"I am happy with the way we played against them. It's not easy to come back from a goal down and win against them. I am happy with the way my players fought back and at the end, they were rewarded. It is a good performance.
"We want to continue giving the best this season and see where we can finish."
Mathare managed to cement their place in the top tier on the last day of a turbulent 2017 season.