Cotterill, who was welcomed with mandatory jeers following a desertion of his managerial post at Stoke four seasons ago, watched as Gray struck to earn Burnley their first away win this term.
The home supporters had barely settled into their seats before the travelling contingent were jumping about theirs in celebration of an extraordinarily early lead.
The scoreboard hadn't even ticked through a minute when Steve Simonsen was forced to watch Gray's drive trickle in after tipping the angled shot onto the inside of the post.
A dreary 44 minutes followed as neither side looked capable of breaching the opposition's backline, Stoke however did have a go.
Darel Russell acrobatically met Andy Griffin's long throw with a point-blank overhead swipe which was comfortably gathered by the fortuitously placed Burnley stopper Brian Jensen.
The Britannia faithful were granted the opportunity to raise a cheer when fan favourite Carl Hoefkens began his first-half warm-up after being relegated to the bench in favour of loan signing Griffin.
The Potteries boo-boys were prompted into stretching their vocal chords when Chris Foy's whistle eventually concluded a truly forgettable first half, and deservedly so.
And when referee Chris Foy's whistle concluded a truly forgettable half of football, the Potteries boo-boys sprung to full voice, and deservedly so.
A half-time roasting seemed to have shaken the hosts into life as City drew Jensen into an acrobatic stop with the second half only a minute old.
A neat lay-off from Martin Paterson gave Peter Sweeney a rare glimpse of goal but his thumping shot was palmed away by the cat-like Burnley keeper.
Despite Stoke's second-half endeavour they were lucky not to be trailing by a greater margin when Michael Duff arrived unmarked in the 53rd minute.
Wade Elliott dropped a sweet centre into the danger-zone which was begging for a killer touch, which, despite losing his man, Duff just couldn't apply.
Mamady Sidibe had a late chance to claw a point for the home side when he pounced on a rare moment of indecision from the Burnley rearguard.
The towering front-man spun and hit a wicked volley which was miraculously pushed over after Wayne Thomas and John McGreal and made a real hash of a routine clearance.