Manager Mark Betts felt that key players absent from Saturday's line-up were sorely missed, in particular new signings Lee Rendell, who was ill, and Meddie Nsubuga, who was unavailable.
However, Betts and his assistant Richard Barnard were keen to look at positives after a strong first half performance that saw the teams go in goalless at the break and promising debut starts from youngsters Luke Van Spall and Tom Windsor.
"We just got mullered in midfield tonight," Betts said after the game. "We were lucky to come in 0-0 at half-time. We'll take the positives and work with that. We are looking forward to Saturday and we'll get a team out to play Winchester."
The Rebels once again lined up in a 3-5-2 formation with new skipper Lee Riddell as a sweeper, scorer from the weekend Jermaine Gumbs up front and Oxford loanee Mark Janes at right wing-back. However, the influential Rendell was missing as well as brothers Abbey and Meddie Nsubuga, which left the midfield in particular short of experience.
Hillingdon enjoyed most of the pressure in the first half but Slough created the best two chances by far. On 25 minutes, Chima Eberendu dummied a ball out of defence to get away from his maker and cut inside from the right. He floated a cross over to his strike partner, Gumbs, who was free in the middle, but somehow managed to scuff his header just yards in front of the goal.
A scrappy game saw half-chances for the home team as they kept possession well and probed for gaps. But Slough displayed an improved defensive organisation, which saw them winning balls played into the box, picking up runners and keeping their shape.
Eberendu should have opened the scoring just five minutes before half-time when he engineered a great opportunity for himself. The tall striker turned one marker before powering through the next and drove into the box before losing his composure at the crucial moment and powering a shot onto the crossbar.
After the break it looked as though the Rebels would continue where they left off as only a last-gasp tackle prevented Van Spall from getting a shot in on goal.
However, two goals in two minutes from the hosts effectively killed off any resistance.
The first goal was a touch fortunate as Sam Byfield's shot from the edge of the area was deflected past a helpless Barnard.
The second was more avoidable, however. Slough were still rattled by the first and allowed Warren Waugh far too much time and space to curl in a shot from the corner of the box.
Two poorly defended set pieces then put the result beyond all doubt. Mark Kirby volleyed in unmarked from a free-kick after 65 minutes and Max Howell escaped his man at a corner with ten minutes remaining.
Slough did manage a late consolation when second-half substitute Tom Attrell worked hard to get to the byline and cross for Gumbs to power a half-volley into the back of the net.
Hillingdon Borough Line up
1. Matt Davis, 2. Gavin Brown, 3. Danny Bennell, 4. Max Howell, 5. Nick Turner, 6. James Duncan (c), 7. Chris Hibbs, 8. Mark Kirby, 9. Warren Waugh, 10. Leon Nelson, 11. Sam Byfield Subs: 12. Danny Tilbury, 14. Dave Lawrence, 15. Chris Phillips, 16. Kevin McKenna, 17. Franco Strange