Kashiwa Reysol forward Olunga drilled in a late winner, having earlier made it 1-1 with a superb overhead kick and also heading against the crossbar.

Tanzania had gone ahead twice through Simon Msuva's tap-in and Mbwana Samatta's effort for a half-time lead.

Johanna Omolo flicked in a header at the near post for Kenya, before Olunga struck with just 10 minutes remaining.

The result moves Kenya level on three points with Senegal, who were beaten 1-0 by leaders Algeria, while Tanzania exit the tournament still searching for their first victory.

Kenya play Senegal and Tanzania face Algeria in the final group games on Monday at 20:00 BST.

Analysis

BBC Sport's Nick Cavell at 30 June Stadium

This really was a proper local derby. Lots of tackles flying in, lots of time spent with people on the floor getting medical attention. But on top of the feistiness, there was some really nice football from both sides throughout the game.

It wasn't maybe the prettiest game that anyone's ever seen, but there was a lot in there - Tanzania twice taking the lead, Kenya coming back twice and eventually winning, to give themselves a chance of going through.

Mbwana Samatta was excellent for Tanzania - everything flowed through him - but Kenya had Michael Olunga, whose very well-taken goals saw them win the game.

They have left Tanzania heartbroken - the first team to be officially eliminated from the Africa Cup of Nations.