The victory came at a cost though with stand-in captain Jamie Peacock sure to be a doubt for the Challenge Cup final against Warrington in a fortnight's time having had to be helped off with a knee injury in the second half.
After a lengthy stoppage for treatment, fellow prop Luke Burgess was also stretchered away in the closing stages with a suspected broken jaw following a thunderous collision with young Castleford front-row Jonathan Walker and Rhinos' Kiwi second-row Ali Lauitiiti could be in trouble with the disciplinary having been placed on report for a high tackle on Stuart Jones.
Coach Brian McClennan left out four players with niggles but each would have played if yesterday had been that final.
Regardless, the absence of captain Kevin Sinfield, Brett Delaney, Danny Buderus and Ryan Bailey did not weaken the champions who – despite the one-sided scoreline – had to protect their line as fiercely as they had done all season to thwart a Castleford side that was eventually left bewildered.
Despite almost constant pressure, they could not break their relentless visitors who continually scrambled and hustled until Steve Snitch finally dived over in the 72nd minute.
Leeds's defensive attitude was summed up when hulking second-row Ian Kirke remarkably chased down winger Kirk Dixon with just seconds remaining. Equally so, the home side's profligacy was demonstrated straight after when the otherwise excellent Rangi Chase inexplicably spilled a pass with the line at his mercy.
Leeds remain in touching distance of Hull FC in fourth but Castleford – following a third straight defeat – see their top eight hopes finely in the balance.
Coach Terry Matterson had pressed on his players to make the most of their opportunities after missing out narrowly in their last two fixtures against Crusaders and Hull KR.
But their finishing was again indifferent and, against a side of Leeds's quality, they were always going to be punished.
In fairness, the hosts had their fair share of bad fortune, Michael Shenton just denied getting the ball down after a desperate late shove from Lee Smith, a Chase grubber wickedly eluding Joe Arundel and Craig Huby getting dragged down just short after wonderfully evading Peacock.
Jones also made a blistering break but only had Ryan Hudson in support who simply did not have the legs to finish.
However, other promising positions – they had ample – were ruined by poor execution.
Leeds were denied early on when Hudson's splendid cover tackle forced Scott Donald – back in after being dropped for last week's cup semi-final – to fumble as the winger stretched towards the line but three tries in 13 minutes midway through the half ensured there would be no dramas.
Danny McGuire raced onto Greg Eastwood's off-load to weave his way forwards before finding the supporting second-row Chris Clarkson, the young bricklayer who is looking increasingly a Super League force.
Matt Diskin shrugged off Huby on halfway before feeding McGuire who then cheekily dummied McGoldrick to slide over despite the best attempts of Arundel and continue his impressive run against this opposition; it was the England stand-off's 19th touchdown in just 14 games with the Tigers.
If one slippery, elusive half-back was not bad enough for Matterson's men, Leeds also had Rob Burrow buzzing around and he added the third with a comical effort, barely needing to duck as both Stuart Jones and Liam Higgins went high.
Lauitiiti continued the scoring after the break when he latched onto Paul McShane's break and just as Castleford looked finally to have exposed Leeds, Ryan Hall nipped in to snaffle a McGoldrick pass and race untouched 80 metres to the line.
After Castleford had wasted another chance – leaving the frustrated Chase shaking his head in disbelief – Brent Webb showed them how to make the right decision and commit defenders with a clinical pass that ushered Donald over for Leeds's sixth try.
Steve Snitch immediately spilled Chase's next pass with the line begging but he did finally get over although Hall had the last word with his second in front of a crowd of 7,901.
CASTLEFORD are understood to have signed Australian winger Nick Youngquest from Crusaders for 2011.
The 27-year-old former St George's player has scored nine Super League tries for the Welsh club this season.
Castleford Tigers: McGoldrick; Dixon, Shenton, Arundel, Wainwright; Westerman, Chase; Huby, Hudson, Sargent, Snitch, Clayton, Ferres. Substitutes: Jones, Widders, Walker, Higgins.
Leeds Rhinos: Webb; Donald, Senior, Smith, Hall; McGuire, Burrow; Leuluai, Diskin, Peacock, Kirke, Eastwood, Clarkson. Substitutes: McShane, Burgess, Jones-Buchanan, Lauitiiti.
Referee: Richard Silverwood (Mirfield)