Castleford: (14) 38
Tries: Westerman, Donlan, Dorn (2), Shenton (2), McGoldrick
Goals: Westerman (5)
Leeds: (6) 20
Tries: Donald (3), Tansey
Goals: Sinfield (2)
Castleford claimed their first win of the season with a shock victory over World Club champions Leeds.
The Tigers showed great resolve after trailing early on to a try from Scott Donald, who finished with a hat-trick.
Joe Westerman, Stuart Donlan and Luke Dorn all responded to give the Tigers a healthy half-time advantage.
They dominated matters after the break with Michael Shenton crossing twice while Ryan McGoldrick and Dorn also went over for a well-earned win.
The Rhinos, who had put in a superb effort to beat Melbourne Storm last week, began well when Kevin Sinfield and full-back Brent Webb combined to send Donald in after 16 minutes.
Sinfield added the goal but it took Castleford only four minutes to strike back through teenage loose forward Westerman who regathered his own grubber kick 10 metres out from the Leeds line to touch down.
The conversion was missed but the confident Tigers were on a roll and Donlan, on his return from injury, was sent in after Dorn and Brent Sherwin created the space for McGoldrick.
Dorn then timed a run to perfection to follow up Sherwin's grubber kick and claim a third try, which Westerman converted.
Leeds looked threatening with the ball but committed a series of handling errors and did not look their usual fluent selves.
Shenton scored two tries within three minutes of the restart, the first set up when Donlan went past Keith Senior and the second when he dummied over.
Donald went over twice in the space in seven minutes but the Tigers pulled ahead again on 61 minutes when McGoldrick sliced clean through the visitors' defence for a sixth try.
Westerman edged his side further in front with a penalty before Jordan Tansey scored a consolation try for the Rhinos but Castleford finished in total control, with Dorn racing in for his side's seventh try, and Westerman took his goal tally to five from eight attempts.
Castleford coach Terry Matterson
"I was confident we would win. I felt something was brewing.
"But we made it hard for ourselves. We bombed some tries you wouldn't think you could bomb so there is a lot of improvement.
"I'm real proud of the boys. But we've got to make sure it's not a one-off. We've got to be consistent."
Leeds coach Brian McClennan
"I don't want to disrespect the way Castleford played. They were great. They really aimed up and scored some wonderful tries.
"They were probably unlucky not to win by more. If they had kicked their goals in the first half, it would have been worse for us.
"We're all really disappointed with how we performed. But that's sport. We had a glorious high last week and now we're on a low. We'll have to dust ourselves off and get ready for Harlequins next week."
Castleford: McGoldrick, Donlan, Shenton, Dixon, Wainwright, Dorn, Sherwin, Huby, Moore, Korkidas, Guttenbeil, Lupton, Westerman.
Replacements: Henderson, Leafa, Higgins, Clayton.
Leeds: Webb, Smith, Gibson, Senior, Donald, Tansey, Burrow, Bailey, Diskin, Leuluai, Ellis, Jones-Buchanan, Sinfield.
Replacements: Lauitiiti, Scruton, Ablett, Burgess.
Referee: P Bentham (Warrington)