Wigan Warriors fought hard to see off Leeds Rhinos after St Helens had held Castleford Tigers scoreless in Super League.
Totally Wicked Stadium staged both top-flight contests on Sunday, with Saints briefly taking over at the top of the table thanks to a 10-0 triumph at their home ground.
However, Wigan moved above their rivals to sit two points clear at the summit as they won 28-10 against Leeds, who have now lost two on the spin after going down 48-0 to St Helens last time out.
The Rhinos did put in a much-improved display, however, and were right in the contest until the closing minutes, trailing just 16-10 after Liam Sutcliffe charged through a gap to reach the line.
Luke Gale set up the try but was sin-binned soon after, allowing the Warriors to ease clear against 12 men. Bevan French crossed twice in the game, while Liam Farrell registered his 100th try for Wigan.
Reigning champions Saints had earlier shut out Castleford, Theo Fages going over for the only try in the closing minutes following a break from James Roby in his 500th career appearance.
The rest of St Helens' points came from the boot of Lachlan Coote, who kicked three goals after the break following a scoreless first half.