Bradford (6) 10
Tries: Worrincy, SheriffeGoal: Sykes
Leeds (6) 6
Try: Jones-Buchanan Goal: Sinfield
Sheriffe's score came at a crucial time for the Bulls
Bradford bounced back from their Challenge Cup exit last weekend with a morale-boosting win over rivals Leeds.
After Jamie Jones-Buchanan put the Rhinos ahead, the Bulls rallied superbly for Michael Worrincy to level it up six minutes before the break.
The Bulls continued to dig deep after the break but Paul Sykes missed two penalties to leave the game in the balance with 20 minutes to go.
But Rikki Sheriffe crossed on 68 minutes for the match-winning score.
The Bulls were also given a late scare with four and a half minutes left, when Danny McGuire had a try disallowed by video referee Thierry Alibert for a knock-on in the build-up.
It was the second time Alibert had controversially denied the champions in the game, with Rob Burrow also having his score on the hour mark chalked off.
Bradford looked the livelier side from the start but the Rhinos soaked up the early pressure and took the lead with their first serious challenge into opposition territory midway through the first half.
Jones-Buchanan took a suspiciously forward-looking pass from Burrow to force his way over for the game's first try and Kevin Sinfield added the goal.
Leeds looked like they had extended their advantage on 31 minutes through winger Ryan Hall, but play was brought back for a forward pass.
The Bulls made the most of the let-off and drew level six minutes before the break when substitute Worrincy took Sykes's pass and wrong-footed full-back Brent Webb for his first try for the club.
Sykes added the conversion to level the scores before Sinfield missed a tricky penalty from the halfway line on half-time.
Leeds looked to be gaining the ascendancy in the third quarter but they committed some uncharacteristic errors.
However, they looked to have made the breakthrough on the hour when Burrow broke clear from deep inside his own half and took a return pass from Webb to touch down, but their joy was short-lived.
The drama continued when Webb lost the ball on his own line but was deemed to have made it dead and then Leeds had Ablett sin-binned for dragging Sheriffe into touch after completing the tackle.
The former Harlequins winger was looking dangerous and he claimed the game's crucial score after Ryan Hall had failed to deal with a Ben Jeffries high kick.
Sheriffe ought to have scored again after Menzies broke clear and it looked to be a costly miss when young winger Kallum Watkins broke away for McGuire to finish off the move.
However, Alibert once more disallowed the try, ruling Jones-Buchanan had knocked on in the build-up and Bradford made the most of the reprieve to hang on for a precious win.
Bradford coach Steve McNamara:
"It was a big kick in the teeth for us last week so to get the job done, I'm just pleased for the group.
"It was a very tight, tough game. There was not a lot in it. I thought there was some tremendous spirit and determination from us and some quality there as well so I'm very pleased.
"We started the last two games well but tonight we continued in that vein. They all played very strong. Steve Menzies played four different positions and he didn't look out of place in any of them."
Leeds coach Brian McClennan (on the decisions of the video referee):
"I've got thoughts about them but I'll keep them to myself. I don't want to take away what Bradford did.
"There was a lot of desperation and a lot of courage in their play. You could see a side that really needed those two points and they did a good job and played tough.
"I'm actually pretty pleased with some aspects of our game. Our defence was a lot better. We just didn't get cracking along in attack but that's credit to Bradford."
Bradford: Halley, Sheriffe, Sykes, Nero, Tadulala, Menzies, Jeffries, Lynch, Newton, Kopczak, Langley, Cook, Burgess.
Replacements: Scruton, Platt, Crookes, Worrincy.
Leeds: Webb, Watkins, Ablett, Senior, Hall, McGuire, Burrow, Leuluai, Diskin, Peacock, Jones-Buchanan, Kirke, Sinfield.
Replacements: Burgess, Buderus, Lauitiiti, Bailey.
Referee: I Smith (Oldham)