McDermott looked pleased with himself when he unveiled two new signings - Corey Browne from Stevenage Borough and Danny Bailey from Exeter City - in a side which featured four debutants and a total of eight men acquired directly from the pro game, until...
Crash! The shaven-headed Bailey received a deep cut on his crown after an early aerial crash with Craig Norman and it looked for a while as though his day was over.
Bang! During the 10 minutes when Bailey was off the field getting treatment the Poppies struck the opening goal.
From a 10th minute free kick on the right, David Hercock's low cross was flicked goalwards by Peter Costello and drifted just out of the reach of a scrambling Ben Miles.
And wallop! Gary McGinnis had to retire in the 18th minute with a hamstring problem after a challenge with Costello, further denting that pre-match optimism and posing crucial questions perhaps sooner than McDermott would have liked.
Two big deficiencies when Slough hit their mid-term low last season were balance and confidence - and these were quickly put to the test.
Though the Rebels went into the interval a goal down, there were signs that both these factors have been, at least on this performance, improved.
Better communication all-round-produced some promising-interplays up front between Brazil, Abbott and Bolt, the latter being set up with two goal-scoring chances which foundered mainly through a lack of conviction.
That changed in an all-action second half with Bolt - wracked with self-doubt for much of last season after a reckless penalty miss - bubbling with start-of-term enthusiasm.
The Rebels levelled the game with a carbon copy of Kettering's opening goal only this time it was Bolt's deftly floated left-foot free kick in the 46th minute which eluded Brazil but found Abbott's outstretched boot at the far post.
Bolt made the next three minutes later, standing up to a series of midfield challenges before releasing Randall on the right, who first timed to Brazil in the opposite corner.
Hardyman made an instinctive and incisive drive to the post, then stabbed low for Randall to crash home on the burst. Referee Pashley was lenient when ticking off Browne, who had been booked early in the game for petulance.
But he showed Hercules no mercy moments later for a foul on Costello which saw Norman stroke the Poppies back into the lead on 54 minutes from the penalty spot.
Back roared the Rebels four minutes later as Sheppard flapped at a cross from the right and Browne popped the ball up for Abbott to get the vital touch from close range.
The Poppies seldom enjoyed that sort of penetration and their third goal in the 72nd minute came from another set piece, a free kick tapped to Norman who drilled it low from the right into the opposite corner.
The final 15 minutes belonged to Slough's youngsters, with Owusu eventually joining in as Bolt and Randall willingly took on Kettering's defence.
The teenaged Randall in particular displayed an unflappability from which Bolt seemed to feed. Poppies' player-manager Steve Berry came in for some harsh treatment from the home fans for indecision when former Wycombe striker Micky Nuttell became the worse for wear in his battle with Hercules.
McDermott led an angry bench protest when Abbott netted what looked like his hat-trick after being put clear in the 90th minute, only for the goal to be ruled offside.
The Slough boss was denied all three points, but felt the moral high ground was his.
That his Rebels conceded three set-piece goals - one, admittedly, a penalty - may irritate McDermott who has made securing the defence his priority during the close season.
That they replied twice from open play suggests that his side has a new creative dimension, but one which will have to stand the test of time.
Kettering Town Line up
Shepphard, Ridgway, Mutchell, Gaunt, Tucker, Vowden, Pick, Norman, Nuttell, Costello, Hercock. SUBS- Pearson, Wilkes (86. for Nuttell), Berry (73, for Tucker)