St Helens' patched-up team continued to exceed reasonable expectations with a second-half battering of the team that was for so long their main rival at the top of Super League.
After a tight first half, Saints blew the Rhinos away in the third quarter, with their enterprising young scrum-half, Jonny Lomax, always prominent.
It was the sort of display that will ensure nobody takes Saints lightly this season, while confirming that for Leeds it is, at best, a season of transition.
In their own, relatively quiet way, Saints' achievement in keeping pace with the Super League leaders has been one of the stories of the season so far. Disrupted by exile in Widnes, by injuries and impending departures, they have still managed to keep up their standards.
The main reason Saints have got away with it has been the quality and preparedness of the young players they have been forced to throw in and there was an implied respect for their capabilities in the way Leeds accepted two points from an early penalty, rather than running the ball in their traditional style.
Paradoxically, when the Rhinos were awarded another penalty, they did run it, with Lee Smith very nearly scoring in the corner.
Saints' best chance came when James Roby raced away from a blind-side scrum move, but could not find a man in support and was hunted down by Brent Webb. When Leeds got their off-load game working, their surge upfield produced another penalty and a second goal from Kevin Sinfield.
Saints had their noses in front by half-time, however. Brett Delaney was penalised in the tackle to give them extra possession and, from Roby's dummy-half pass, James Graham forced his way over from close range, with Jamie Foster adding the goal.
Saints found a different gear after the interval. The try that put them in control would have delighted any St Helens line-up, in any era. Louie McCarthy-Scarsbrook did superbly to keep the ball alive, but the real architect was Lomax, a player many feel might have been worth a place in this week's England squad.
He bounced out of a series of tackles to serve the ball up for Roby and Saints were already disappearing out of sight before Leeds conceded another, largely self-inflicted try when Sinfield kicked straight into the hands of Francis Meli. Another dazzling move ended with Lomax supporting Meli for another copybook score. Leeds put the kick-off straight out to sum up their evening and pave the way for Scott Moore to join in the fun. A wonderful pass from Jon Wilkin put Paul Wellens over, although Jamie Jones-Buchanan got one back for the visitors, who registered again through Smith, before Lee Gaskell rounded it off with a last-minute interception.
It was a victory that came at a cost for Saints with Roby suffering a suspected eye socket fractrure. On this showing, they will find someone to take over seamlessly, even from him.
St Helens: Wellens; Makinson, Shenton, Meli, Foster; Gaskell, Lomax; Graham, Roby, McCarthy-Scarsbrook, Soliola, Wilkin, Puletua. Substitutes used: Eastmond, Moore, Dixon, Magennis.
Leeds: Webb; Hardaker, Smith, Delaney, Hall; McGuire, Burrow; Leuluai, Buderus, Peacock, Jones-Buchanan, Ablett, Sinfield. Substitutes used: Lauitiiti, Bailey, Hauraki, McShane.
Referee: P Bentham (Warrington)Reuse content