Horsham slipped to fourth following a second successive defeat - 28-8 - against one of the promotion contenders.
The Green and Whites have not beaten Charlton Park since being promoted to London 2 South East and never looked likely to break the sequence on this showing.
Horsham can take solace from the realisation that Hove are the only one of the top-six sides the Green and Whites have not faced in their opening six games.
With both sides being affected by a strong cross-field wind, Park dominated from the outset going through multiple phases, and pressurising Horsham into conceding a succession of penalties.
Park’s Sam Baker came close to went close to opening the scoring, before a great last-ditch tackle by Josh Mills to stop a likely try for Reion Raybe. Park then kicked for a line-out 10 yards from the try line and put together a powerful catch and drive from which Baker scored.
This galvanised a response from Horsham as they mounted a period of pressure in the Charlton half but an ability to secure their own line-out ball continued to be a problem.
When Park conceded a penalty, Tom Johnson pushed his attempt at goal just wide of the right-hand upright.
Finally Horsham’s backs cut loose from deep in their own half, and after the ball had passed through several sets of hands, it reached Steggles who would have scored but for a great cover tackle by Raybe.
The pressure was maintained when Jonny Whiting broke off the back of the scrum and powered through the first defender but he knocked the ball forward in the next tackle just short of the line.
Park came back on the stroke of half-time with a penalty from Alan Knuckey to increase their lead which was the least they deserved.
Charlton continued the second half in a similarly dominant vein but were profligate with taking their chances.
Horsham suffered injuries to Johnson and Mike Watts in close succession and while both were being treated, the team mounted an audacious counter attack from their own 22 with only 13 fit players on the field when Johnny Ordidge led a break-out which nearly lead to a score.
Park conceded a penalty which Wilde calmly slotted as Johnson was helped off the field.
Charlton soon bounced back when open-side flanker Baker broke through with Knuckey in support to notch another try, a 15-3 lead and confirm his position as one of the leading try scorers in the league this season.
Park thought they had stretched further ahead when their winger ran 50 yards, only for the ball to be knocked forward in the tackle just short of the try-line.
Horsham went through the phases to try to retain possession and make their way out of their 22 but then winger Jeremy Montes ran in a simple try off a turnover.
Hooker Ed Mason scored a try to seal the win for the home side, although the conversion was again missed making the scoreline flatter the visitors at 25-3.
Horsham did not allow their heads to drop and after a fine multi-phase attack, the defence was committed to allow Ryan Maguire a simple run around to score under the posts.
“It was a very disappointing performance with the team only showing some of its potential for the final two minutes”, Horsham head coach Nick Stocker said.
“I would assess a two out of 10 as we lacked appetite for the fight which was the most disappointing aspect of the performance.
“Although Charlton Park missed a few try scoring opportunities, we also left a number out there and we needed to play more cohesively as a team than a collection of individuals that we saw.
“We will need to banish this and make sure we perform far better in the weeks ahead, beginning with a tough local derby at home versus Pulborough next week.
“We will also certainly look forward to a rematch against Charlton Park later in the season with an opportunity to right the wrongs.”
Horsham: Watts; Steggles, Ordidge, Wilde, J.Bell; Johnson (Maguire), Mills; Fairs, Stone, N.Bell (Cass); Clarkson (Goward), Tredgett; Carvell, Smith, Whiting