Inside the opening 15 minutes, the away side were by the far the better team which showed as they opened their tally in the 11th minute.
Simeon Jackson curled an effort into the bottom corner from outside the box.
Slough grew more into the game following the goal and controlled the game throughout.
On the 34th minute, Lench whipped in a corner to Hollis, who just headed over the bar.
Just before half-time Slough had their best chance of the game, Lench with a powerful strike from 30 yards out which was saved around the post by goalkeeper Ejeheri.
The second half proved to be more Slough dominance, creating chance after chance to try and find an equaliser.
Johnny Goddard’s header from Josh Jackman’s cross at the far post went straight into the arms of Ejeheri.
Then just a few minutes after, Goddard fed Elliot Benyon through on goal, but he scuffed the shot wide of the target.
Then with 10 minutes to go, Chelmsford doubled their lead from a counter-attack as Devonte Aranzubia took the ball around Jonathan North and tapped it in.
Slough then put as many players as they could up the pitch to try and muster a late comeback, with the closest opportunity coming when George Hunt came on and hit the woodwork in the dying embers, which summed up the frustration of the Rebels on the night.
Chelmsford City Line up
Ejeheri, James, Barnum-Bobb, Trotter, Oluwo, Aransibia, Lodovica, Jackson (c), Blackwell, Da Costa, Vaz. Substitutes: Winfield, Hockey, Jones, Ochieng, Ruff.