Challenge Cup winners and Super League leaders Leeds Rhinos were beaten 32-18 by a St Helens side who ran in five tries at Headingly Stadium this evening.
The result is the Rhinos' first defeat in this season's Super 8s.
Tommy Makinson capitalised on an early Rhinos error to put his side ahead, but Jimmy Keinhorst levelled the game midway through the first half.
Josh Jones then wrestled the lead back for St Helens with the help of the TMO, before a Luke Walsh penalty edged the visitors 14-6 ahead.
However, a Mitch Achurch score ably converted by Kevin Sinfield reduced the gap to just two at the break.
Walsh went over shortly after the restart for the visitors, and Adam Quinlan extended the lead when he collected a Travis Burns pass and crashed over.
The Rhinos set up a grandstand finish when Ryan Hall's try nine minutes from time brought the difference down to eight points, but a late Jon Wilkin try ended their hopes of a fightback.
