Macharia scored the Brewers' second goal in the 63rd minute to add to Omary’s opener in the 17th minute and help Robert Matano's side to temporarily jump to fifth, pending the outcome of the match between Ulinzi Stars and Nakumatt.
Tusker really needed maximum points after dropping two points against Sony Sugar last time out. The victory saw the former champions take their point tally to 43, two more than Ulinzi Stars. Chemelil in the meantime, remained winless in four games.
The millers are third from bottom with 28 points and they will have to move up to avoid the relegation play-off. In the other match played on Wednesday, Kariobangi Sharks condemned another relegation candidates, Thika United to a 3-0 victory.
The victory was a second in a row for William Muluya who has now set focus on finishing in top-five. Elsewhere, Sofapaka beat Posta Rangers by a solitary goal to maintain their fourth place on the log.