Last week's vital victory at relegation rivals Wakefield Trinity gave Castleford some much-needed breathing space at the bottom and may yet prove decisive – but there were concerning signs in the rout by Saints.
The four-time defending champions picked Castleford apart with worrying ease and the hosts looked like a beaten side long before referee Aaron Moore put them out of their misery.
The Jungle is a notoriously difficult assignment for visiting sides but the Tigers have lost their bite in front of their own fans, Saints inflicting a 10th home defeat of a miserable season.
Huddersfield Giants finished off Andy Last in Castleford's previous outing at Wheldon Road and Saints made it a miserable first home game in charge for Ward with a performance that hinted at another big finish for the Super League kings.
St Helens raced into a 30-0 half-time lead and had the luxury of taking their foot off the gas as a forgettable match petered out.
Wakefield's 20-0 loss at Salford Red Devils limited the damage but Ward will know the Tigers cannot rely on Trinity firing blanks in the remaining four rounds.
Castleford's cause was not helped by the loss of five players from the team that inflicted a significant blow on Wakefield, hat-trick hero Greg Eden and recent signing Blake Austin chief among them.
There was no sign of the onslaught to come in a lively start by the Tigers that should have yielded the opening try.
Saints put themselves under pressure after failing to deal with two high kicks but they demonstrated their champion qualities to defend their errors.
Jon Bennison denied Charbel Tasipale with a superb last-ditch effort before Liam Horne was dragged down just short of the tryline by another desperate tackle.
That was as close as Castleford came to troubling Saints in a depressingly one-sided first half from a home perspective.
Ward was forced into an early reshuffle after losing Will Tate to a leg injury and St Helens were in an unforgiving mood.
The floodgates opened in the 11th minute, Mark Percival sending Tommy Makinson into space on the right wing and racing through to take the return pass and score his 100th Super League try.
The centre added the first of five impressive first-half conversions from the touchline to make it 6-0 – and Castleford were unable to turn the tide.
Gareth Widdop tried his best with an unorthodox tackle to deny Sione Mata'utia just short of the line but it only delayed the inevitable, Makinson burrowing his way over in the corner in unconvincing fashion.
Widdop's hard work went unrewarded again minutes later when Bennison stepped back inside to finish under the sticks after Jack Welsby was somehow held up by the Castleford full-back.
The Tigers were in damage limitation mode inside the opening 25 minutes but they could not stem the bleeding.
Joe Batchelor cruised over after backing up a break by Welsby and the talented full-back was the provider for Makinson's second try with a classy cut-out pass.
Half-time gave Castleford the chance to catch breath but there was nothing Ward could say to swing the momentum in the home side's favour.
It took St Helens all of five minutes to open their second-half account following another crisp move to the right that ended with Makinson getting away a superb offload for Jonny Lomax to finish.
Percival blotted his copybook with his first miss of the night from out wide but it mattered little.
Saints threatened again when Bennison ran into space on the left flank but Elliot Wallis got back to drag his opposite number into touch with a forceful tackle that underlined the frustration in the home ranks.
Castleford rallied in the final quarter to give their supporters some reasons for encouragement as they switch their attention to next week's trip to Warrington Wolves.
Sam Hall galloped into space from Liam Watts' pass and after the prop was caught high, the Tigers got on the board through the departing Jordan Turner following a well-worked move to the left.
Saints lost Sam Royle to a yellow card for a professional foul in the closing stages but Castleford could not take advantage, Wallis coming closest when he had a try ruled out for a forward pass.
Castleford Tigers: Widdop, Wallis, Tasipale, Turner, Tate, Westerman, Miller, Watts, Horne, Griffin, Edwards, Mellor, Lawler. Substitutes: Hall, Johnstone, Foster, Tsikrikas.
St Helens: Welsby, Makinson, Davies, Percival, Bennison, Lomax, Dodd, Knowles, Roby, Delaney, Mata'utia, Batchelor, Bell. Substitutes: McCarthy-Scarsbrook, Norman, Royle, Mbye.
Referee: Aaron Moore.