An understrength Harrogate Pythons side slipped to their seventh defeat in eight games when they lost out 21-0 at Castleford.
With a number of senior players missing, several players from the club’s 2nd XV were included in Dan Bird’s squad for their visit to Yorkshire Three’s eighth-placed team.
The Pythons started solidly, with possession being ripped from the hosts by an Ian Binns turnover, but the ball was then lost cheaply following a bad offload by Sandy Dunlop.
The visitors’ scrum looked sound enough with Nathan Wake, Steve Smith and Ted Illingworth providing a stable front row platform.
From one such set-piece, Ivan Drane made a characteristic break on the blind side before Ollie Wheatley was stopped just short of the home try-line.
Wake then took the ball on the crash but was isolated from his support and a turnover allowed Cas to escape.
As the hosts attacked down the middle, Matt Leach was penalised for a high tackle and the resulting kick at goal handed Cas a 3-0 lead on 10 minutes.
Shortly afterwards, another Harrogate infringement in midfield led to Cas doubling their lead with a second penalty.
As the Pythons went in search of a way back into the game, Drane again combined well on the blind side with Wheatley, who set up a driving maul deep in home territory.
Wake charged for the line but was stopped and Cas were eventually penalised.
Harrogate elected for a scrum and Drane was again caught just short of the line before another penalty was awarded and an easy three points were again refused.
The Pythons looked to turn the screw at the resulting scrum, but the ball squirmed out of the back and was well cleared as the hosts took their 6-0 advantage into half-time.
Cas started the second period in dominant fashion with Jack Clarkson on the receiving end of a huge tackle when he received the home kick-off.
Drane rescued the situation with a good clearance to halfway, but from the resulting line-out one of the hosts’ flankers broke in midfield and set a teammate away.
The Cas winger was stopped short by a Dorian Ennequin tackle but possession was recycled and an accurate cross-kick was gathered by the opposite winger who crossed unopposed out wide.
With the conversion then successfully added, Cas had increased their lead to 13-0 within two minutes of the re-start.
Although the West Yorkshire outfit began to dominate territory thanks to some excellent kicking from their fly-half, they were repeatedly knocked backwards by some ferocious Harrogate defence, with Clarkson in outstanding form.
A high tackle then allowed Cas another shot at goal, and this was duly landed for 16-0 after 53 minutes.
The Pythons brought on Ollie Campey for his debut, but by this stage Cas were playing with plenty of confidence and attacking in waves.
They broke from a scrum, but despite an apparent knock-on, play was waved on by the referee a home player powered over out wide to make the final score 21-0.
Tenth-placed Pythons entertain Leeds Modernians at Pennypot on Saturday in what has become a must-win fixture as Bird and his troops look to put some distance between themselves and the relegation zone.