Leamington produced a dominant performance to stem a seven-game losing streak and give themselves hope of avoiding the drop, while condemning their derby rivals to relegation.
In front of a large crowd, Leamington gained early reward, with their pack driving up the flank at speed for number eight Craig Smith to get the vital touchdown.
Buoyed by this early score, Leamington continued to exert pressure on their hosts.
Dan Kane used his blistering pace and power to force his way upfield, finally unleashing a well-timed pass to Ryan Byrne on his outside, who was felled by a high tackle to earn his side a penalty.
Leamington continued to press and got the crowd on their toes with another piece of scintillating rugby.
Alex Carroll, who at fly-half was orchestrating all of Leamington’s attacks, sent in the deftest of inside passes to Tom Daplyn, whose excellent running line opened up a huge gap in the home defence.
OLs were fortunate to clear their lines but as the heat was increased, they were finally undone with another quick Leamington attack.
Mark Baldwin took the ball courtesy of a drive from his forward, and sent in Jamie Harrison for a try in the nearside corner and a ten-point interval lead.
Leamington increased their advantage after the break with a Nathan Earland penalty and he was successful with a conversion minutes later to stretch the lead to 20 points after supplying Byrne with a touchdown.
Little had been seen of OLs as an attacking force but a 15-minute spell mid-way through the second half set Spa nerves jangling.
The pressure was converted into points by two superbly taken tries by young winger Rory Sinnott, the first after a break which took him past four visiting defenders.
Leamington were jolted by the positive response and looked to the the steadying influence of Pete Blunt, Carroll and Tom Greevy to get them back on track.
After they won a penalty, Craig Smith took the opportunity to run at the home defence at pace. He linked up with Blunt who quickly fed the ball out to Carroll on the blind side. With the home defence floundering, Jim Robertson took the pass and crashed over for the all-important forth try.
The relief in the Leamington camp was palpable and when Earland stroked over the conversion, a 17-point lead had been established.
The game had been played at pace all afternoon, benefitting from the excellent playing surface and with the clock running down, Leamington continued to push the hosts back.
A bulldozing run from Scott Peters, deep in the OLs 22, once again caused major problems and opened up space, which Blunt used to get quick ball to Earland. The Leamington full-back had been in impeccable form all afternoon and capped his display by crossing for the final try, which he duly converted.