Leeds United ended Leicester City's nine-game winning run in the Championship with an impressive victory at the King Power Stadium.
Joel Piroe went close in the opening moments for Leeds while Leicester's Abdul Fatawu hit the bar 11 minutes before half-time in a tight first half.
But Leeds were the better side after the break and took a deserved lead when Georginio Rutter converted from close range after Sam Byram's header from a corner was palmed away by Mads Hermansen.
Substitute Kelechi Iheanacho had a late effort blocked for the Foxes before Kiernan Dewsbury-Hall's stoppage-time header forced a superb first save from Leeds goalkeeper Illan Meslier.
Leicester remain five points clear of second-placed Ipswich Town - who have two games in hand - at the top of the Championship, but miss out on a club-record 10th successive league win.
Meanwhile Leeds, who came down from the Premier League with the Foxes last season, cut the gap between the two relegated sides to 11 points and consolidated third place in the table.
Leeds' press caused Leicester problems in the opening two minutes as Piroe blazed an effort wide from 12 yards after Ethan Ampadu won the ball high up the pitch and Rutter put the Dutchman through.
Rutter had a penalty appeal waved away after he went down under a challenge from Cesare Casadei as Leeds continued to have the better of the first quarter, despite Leicester winger Stephy Mavididi looking dangerous down the left.
Casadei took a heavy touch when a dinked ball from Harry Winks found him on the Leeds six-yard line soon after, as the Foxes began to grow into the half.
Ghana international Fatawu did superbly to create Leicester's best first-half chance as the 19-year-old skipped past Byram on the right wing before cutting in and curling a powerful left-footed effort that crashed off the bar.
Leeds broke straight away and Crysencio Summerville went down on the edge of the box under very slight contact on his arm from Ricardo Pereira.
Visiting boss Daniel Farke was booked following protests that his side should have had a penalty.
It was Leeds who upped their game in the second half as Piroe had a shot well saved by Hermansen, while James Justin did well to dispossess Summerville in a dangerous area soon after.
Leicester were ready to bring on Iheanacho for the quiet Jamie Vardy when Leeds went in front as Rutter could not miss.
The Foxes came close to drawing level when Fatawu's volley went over after some excellent build-up play before Iheanacho had a shot blocked as the hosts upped the pressure.
Joe Rodon did well to block Iheanacho's late effort from inside the box before Meslier pulled off a top-class save in the fifth minute of stoppage time as Dewsbury-Hall's back-post header looked destined for the top left corner.
While Leeds are still six points behind second-placed Ipswich, having played two more games, this result appears to bode well for them.
What goes down as just a second league loss suffered by Leicester this season will have buoyed Farke's West Yorkshire side ahead of games against bottom-half teams Rotherham United, Plymouth Argyle and Swansea City.
Leicester City manager Enzo Maresca told BBC Radio Leicester:
"Overall I'm happy with the performance because they competed, we created some chances.
"I don't think we deserved to lose the game, but it's football. We always say the same, we cannot control the results, but we expected them to use their weapons like counter-attacks, it was the game we expected.
"The race is long, 46 games, we cannot think to win, win, win, win, it's normal that we are going to lose and draw games, and win for sure.
"But in the end the most important thing is the way they behave and that tonight has been good - we created chances, tried to play our football and so for me overall it was a good performance."
Leeds United manager Daniel Farke told BBC Radio Leeds:
"To be brave, to play football with courage and to go for it with confidence was the key today.
"When you want to get something in such a game you have to be brave and you have to make sure that you have periods in the game where you bring the game to their half, you press them really high with bravery and when you're good in possession you hurt them with your possession.
"You can't have these periods over 90 minutes, there are also periods where you have to be structured and allow them possession in areas where they can't hurt you and don't offer them any spaces where they can create chances.
"So to bring such a complex performance on the pitch, on the one hand to be brave and our high pressing, to be good with the ball and dominate, but when they are in possession - because they are so good with the ball - to stay disciplined, to stay well structured and have the possession more or less in their own half where they can't hurt you, I think that was definitely the key today."