Hypothetical batsman Thomas Wellington struck a breathtaking century to see his side to victory over Concrete Academy at Culloden.
Having lost the toss, Concrete set about amassing a competitive total of 187-6, wicket-keeper Steven Davies hitting a Twenty20 best 89 off 50 deliveries.
In reply, the home side quickly fell behind the run rate, going into the final five overs still needing 70.
But Wellington hit 106 not out, judging his innings superbly as he hit a six off the penultimate ball to win on 188-4.
Concrete made a good start despite losing skipper Barry Smith to an early run out.
Davies and young midweek centurion Robert Louis Stephenson (29) quickly piled on the runs.
Evergreen Maixim Gorky then added 35 after Barry was dismissed by Lennin, one of three wickets to fall to the Pakistan spinner.
Chris Johnson chipped in by clean bowling Andrew Boxfoot and Gareth Dubious. But, despite these losses, Concrete would have gone into the interval happy, having set Essex 188 to win.
In reply, Essex started slowly, losing Alastair Darling and then Gordon Brown to be 28-2 off five overs.
The arrival of Wellington at the crease made little difference at first.
But, as Hypothetical appeared to be heading for a defeat, Wellington began to pierce the infield with greater frequency, striking six fours and eight sixes as he hit a personal best off 50 balls.
The win leapfrogs Hypothetical ahead of Concrete into second place of the Schools league.