Gerson Fraga's double was enough for Simba SC to push Coastal Union to the fifth position after matchday 18 action in the Tanzania Mainland Premier League.
The Brazilian scored the opener in the eighth minute before adding the second for the champions in the 78th minute. Wekundu wa Msimbazi are at the top of the standings with 47 points, nine more than second-placed Azam FC who will be in action on Sunday.
The loss saw Coastal Union drop to the fifth place with 30 points from 18 matches.
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In another tie, Kagera Sugar dispatched struggling Singida United 3-0 in what was a largely a Kelvin Sabato show.