The hosts raced into a first-minute lead and soon added a second before going on to dominate the first half with the wind at their backs.
Although Chorley got back into the game shortly after the break, they were unable to find a second goal and went down to defeat for the first time since mid-November and for only the second time in 23 league matches.
The hosts took the lead with just a minute on the clock when a left-wing cross was headed beyond Matt Urwin by Dan Turner.
The Magpies had a chance to equalise almost at once but Adam Senior headed wide from Brad Holmes’ prompting.
Then Connor Hall was clean through on goal only to lift his shot over the keeper but also over the bar.
Leamington doubled their lead after 13 minutes, Kelsey Mooney scoring with a thunderous shot from the edge of the box.
The home side stayed well on top up to the interval, Mooney missing a clear chance with a scuffed effort off-target when left with only Urwin to beat.
Holmes revived Chorley’s prospects after 48 minutes with a simple finish when keeper Jake Weaver dropped the ball at his feet from a long throw-in.
At the other end, Mooney struck a post as Leamington remained dangerous on the counter.
The Magpies kept pressing and were denied an equaliser by a clearance off the line from substitute Ollie Shenton.
Moments later Holmes tested Weaver with a fierce drive .
But the visitors were unable to maintain their momentum as proceedings became scrappy and Leamington were able to see out the game without too many further alarms.
Jamie Vermiglio provided his usual honest assessment after the match.
“The weather and the pitch made it very difficult for both teams,” he said.
“We were caught by a sucker punch early on and then done again on the counter.
“We played with greater intensity for a spell in the second half but Leamington managed the game really well and overall deserved the win.
“We’ve had a tremendous run and now we must go on another one.”
That run may well depend on more solid defensive work as one of the league’s hitherto tightest defences has suddenly shipped seven goals in the last three games.
CHORLEY: Urwin, Leather, Baines, Whitehouse, Calveley, Tomlinson (Shenton 45), Ustabasi, Blakeman, Senior (Scarborough 81), Hall, Holmes (Smith 88). Sub (not used): Birchall.