Leeds 14 (14)
Tries: Ellis, Senior
Goals: Sinfield 3
St Helens 18 (12)
Tries: Gilmour 2, Fa'asavalu
Goals: Lyon 3
St Helens survived the second-half dismissal of Man of Steel Jamie Lyon to beat close rivals Leeds and extend their lead at the top of Super League.
Lyon was sent off with just over 10 minutes remaining for a late challenge on Rhinos scrum-half Rob Burrow.
The home side led 14-12 at half-time but would have had a bigger advantage had Lee Gilmour not scored late on.
Man-of-the-match Gilmour crossed again midway through the second half to give Saints a lead they never relinquished.
The Rhinos took the lead on 14 minutes when Great Britain second rower Gareth Ellis took Danny McGuire's well-timed pass to go through a gap and hold off the challenge of Saints full-back Paul Wellens on a 30-metre run to the line.
Captain Kevin Sinfield's landed his 500th Super League goal to put his side 6-0 in front before Saints drew level through Maurie Fa'asavalu, whose effort was given by the video referee.
Leeds soon took the lead again when a sloppy pass by Leon Pryce to Vinnie Anderson was intercepted by Keith Senior who raced 80 metres for a superb try.
Sinfield kicked his second conversion and added a penalty three minutes from half-time, after Saints Willie Talau and Chev Walker of Leeds were both sent to the sin bin for coming to blows.
But Gilmour's first try, converted by Lyon cut the lead to two points and as the rain continued to fall, the error rate increased.
The decisive moment came on 64 minutes when Keiron Cunningham passed to Gilmour who raced into a gap and although he slipped, he quickly got to his feet to cross for his
second try.
Lyon's third goal made it 18-14, but it was to be his last contribution before his dismissal.
Leeds thought they had at least snatched a point when winger Ashley Gibson went over
at the corner five minutes from the end, but he was brought back for a forward pass.
Leeds coach Tony Smith "I thought it was a fantastic game. It was the best game I've seen since Saints versus Hull and was terrific in the conditions.
"There wasn't much between the teams. It was always likely to come down to a
slip-up and we had a couple of little slip-ups.
"I thought Jamie Lyon was very unlucky to be red-carded. He doesn't have any intent to do anything sinister and I've seen a lot worse this year."
St Helens coach Daniel Anderson "I thought Jamie was unlucky to have been sent off but I understood the referee's reaction because it looked worse than it was.
"I thought it was a fantastic spectacle and was a quality performance from two very good teams.
"At half-time I was as pumped up as the players."
Leeds: Tansey, Donald, Walker, Senior, Gibson, McGuire, Burrow, Jones-Buchanan, Diskin, Peacock, Lauitiiti, Ellis, Sinfield. Replacements: Scruton, Millard, Bailey, Poching.
St Helens: Wellens, Gardner, Lyon, Talau, Meli, Hooper, Pryce, P. Anderson, Cunningham, Cayless, Wilkin, V. Anderson, Graham. Replacements: Fozzard, Gilmour, Roby, Fa'asavalu.
Referee: A Klein (London).