A lone goal by Nicholas Kipkurui left a struggling Chemelil Sugar still looking for their first goal in 10 Kenyan Premier League outings.
Hosts Zoo beat Chemelil 1-0 at the Kericho Green Stadium to move two places up in the standings.
Kipkurui struck in the second half, a goal that saw Zoo FC take their point tally to 24 this season.
Chemelil Sugar, who made a complete overhaul of their squad in the June transfer window, held the hosts until the 52nd minute when Kipkurui benefited from a rebound after Richard Aimo punched the ball into play.
Michael Madoya launched on the rebound then delivered a spit pass to Kipkurui, who was better positioned and the forward buried the goal past Aimo.
Zoo moved joint on points with Tusker, both on 24 points.
The win left Chemelil still looking for a first win in three months, since April 15th when they beat Wazito 3-1 at the Mumias Complex.
The Millers, who are 13th on the log, are yet to score a league goal in 900 minutes, after toiling for 10 games without seeing the back of the net.
Zoo Starting XI: Vincent Misikhu, Johnstone Ligare, Sindani Sabiri, Isaac Kipyegon, Dominic Ouma, Geoffrey Gichana, Kepha Ondati, Danson Namasaka, Michael, Nicholas Kipkurui, Bernard. Odhiambo.
Chemelil Starting XI: Richard Aimo, Morris Wandera, Vincent Mahiga, Odhiambo Jacob, Philip Mwangale, Edwin Omondi, Nicholas Akoko, Ochola Francis, Bliss Kityo, Zeka Wakoli, Felix Oluoch.