Scott, who took over from Terry Butcher a fortnight ago, had led Brentford to something of a revival with a win at Wrexham and a draw at League leaders MK Dons, but that turnaround came crashing down with a second-half nightmare following Ben Starosta's dismissal.
Before Starosta got his marching orders for a foul on the edge of the area just before half-time, the Bees had dominated proceedings and could have been a few goals to the good.
In a scintillating opening spell, Lee Thorpe, Alan Connell and Charlie Ide all went close for the Bees before Wycombe hit back with Sam Stockley striking the post.
But Brentford were on top and took a deserved lead with another belter from long-distance specialist Glenn Poole.
In a move that looked to have been worked at on the training ground, Poole volleyed Ide's 23rd-minute corner from the edge of the box into the top corner and past Wycombe keeper Frank Fielding.
Connell and Thorpe both wasted chances to double Brentford's lead before David McCracken almost deflected Ide's cross into his own net.
But Brentford were given a reminder of the danger down the other end when Simon Brown made a brilliant one-handed save from Scott McGleish.
But the match turned on the stroke of half-time when Starosta was sent for an early bath for his foul on Gary Holt.
Although Thorpe fired into the side-netting just after half-time, it proved to be a false dawn as Wycombe slowly took the game by the scruff of the neck.
Sergio Torres fired a warning when his header came back off the bar on 50 minutes, but four minutes later he hit a fine equaliser after Brentford failed to clear their lines.
Four minutes later Brown was forced to make a fine save from Sutton, but Brentford failed to heed the warning and McGleish was left with a tap-in on the hour mark following a mix-up between Brown and his back four.
By now Wycombe were well and truly in control and, as brilliant as Brentford had been in the first half, they were dire in the second. Sutton rounded off the scoring with Wycombe's third goal in ten minutes when he was left free to head in Craig Woodman's cross.
And in truth the score could have been much higher as, in the dying minutes, Brown saved brilliantly from McGleish in a one-on-one before diving at Matt Bloomfield's feet after he had danced through the Bees rearguard.