St Helens suffered a shock 20-10 defeat to Salford at The Willows.
The struggling Reds put in an impressive first-half display to defeat the Super League leaders for only their sixth win of the season.
Stefan Ratchford scored a brace, while Darrell Goulding and Mark Henry also touched down. Jon Wilshere kicked over two goals in the opening nine minutes.
The Saints, who remain four points clear at the top of the table, trailed 16-0 at the break. They scored tries through Andrew Dixon and Francis Meli.
Elsewhere, Wigan crushed Harlequins 40-12 in Super League at the JJB Stadium.
The Warriors move into seventh place after running in eight tries. Pat Richards, Mark Riddell, Karl Pryce, George Carmont and Amos Roberts dived over in the first half, while Joel Tomkins and Thomas Leuluai sealed the rout.
Quins, who stay in fifth position, scored a try in each half from Matthew Gafa and Luke Gale while Danny Orr booted over two goals.
To cap off a miserable day for the visitors, David Howell was sent off in the first half for elbowing Tomkins in the face.
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