|Betfred Super League|
|St Helens (22) 40|
|Tries: Simm 3, Taia, Fages, Naiqama, Smith Goals: Coote 6|
|Leeds (0) 8|
|Tries: Smith, Tindall|
St Helens moved a step closer to a third Super League minor premiership in a row with a win over Leeds that extends their lead at the summit.
Josh Simm scored a first-half treble to add to Zeb Taia's score as Saints opened up a 22-0 lead at the break.
Cameron Smith got a try back for Leeds as they found some second-half rhythm to cause Saints some problems.
Theo Fages, Kevin Naiqama and Aaron Smith restored Saints' order despite Liam Tindall's consolation.
Wigan, in second, recorded a dominant victory over Salford to improve their points percentage to 73.33%, but Saints remain out in front on 80% in their bid to retain their Super League crown.
Leeds celebrated their first Challenge Cup in five years last weekend, but only four of that squad were involved here.
When Saints were good, they were electrifying; hooker James Roby, stand-off Jonny Lomax and full-back Lachlan Coote producing the skills to unlock Leeds' energetic defence.
Naiqama's try was a prime example, engineered by sharp hands to the right, releasing Tommy Makinson for the Fiji captain to push up and support.
Simm has had to be patient for his first Saints try but showed real class to bring up the hat-trick.
He arced in off the left edge for try one, ran over the top of Callum McLelland for the second and took a looping pass from Jonny Lomax for his third.
The grandson of Saints legend Geoff Pimblett, Simm had been prolific in the academy before making his debut last season, and has helped the Red Vee cope with the absence of Mark Percival.
Rhinos boss Richard Agar sacrificed this match in terms of selection against the leaders, particularly with three games next week to add to tonight's loss.
It made for some tough spells for the inexperienced Blue and Amber against a near-full-strength Saints.
However, the energy of pack talent such as Tom Holroyd and Sam Walters helped Leeds even the stats up in the second-half, despite being unable to even up the scoreboard.
St Helens: Coote; Makinson, Naiqama, Simm, Grace; Lomax, Fages; Lees, Roby, Walmsley, Bentley, Taia, Knowles
Interchanges: McCarthy-Scarsbrook, Amor, Smith, Batchelor
Leeds: Walker; L. Briscoe, A. Sutcliffe, Evans, Tindall; Broadbent, Mclelland; Holroyd, Dwyer, Oledzki, Thompson, Walters, Smith
Interchanges: Hall, Donaldson, O'Connor, Harrison