Leicester beat East Midlands rivals Derby thanks to a first-half own goal from goalkeeper Lee Grant.
The only goal came when Jamie Vardy's flick was cleared off the line by Paul Coutts, but the ball hit Grant and went into his own net.
Kieron Freeman had a chance to level in the second half but Kasper Schmeichel kept out his shot.
The impressive Will Hughes shot wide for Derby before setting up Jamie Ward, whose shot was blocked.
Derby v Leicester - a brief history
These East Midlands rivals have been playing each other in the league since 1907, with Derby winning 42 of the 97 matches and Leicester 30.
England Under-21 international Hughes, 18, has been linked with several Premier League sides and put in another eye-catching performance at Pride Park in front of a crowd of 23,437.
Within two minutes he took part in a move that saw Jonny Russell claim he was fouled on the edge of the area - but nothing was given.
Derby continued their early pressure and Craig Bryson fired over before Leicester striker Vardy forced a save from Grant with a drilled effort.
The Foxes broke the deadlock courtesy of Coutt's botched clearance after Liam Moore headed down a corner, and they had a chance to double their lead when Chris Wood was thwarted by a great tackle from Richard Keogh.
Schmeichel denied Freeman an equaliser before Grant saved from Vardy again. Keogh also headed wide as Leicester held on to end Derby's unbeaten start to the season.
Derby manager Nigel Clough:
"We had a great start to the game. We were on the front foot and were creating chances and then around the time of the goal they came back into it. But 10 minutes into the second half, I thought we controlled the last 30 minutes and played some very good stuff.
"There were lots of nearly moments in the game for us but I thought it was a good enough performance to get something and if you deal with the corner, the bare minimum you come out with is a 0-0 and you keep the unbeaten run intact and move on.
"I think defensively they are one of the best sides and one of the most difficult sides to score against but we certainly had enough situations that we didn't quite turn into chances but we had enough in the second half to get a goal.
"We are OK, we are in good spirits. We know we've played well again and we are happy with the squad and the way we are trying to play. We've had a little setback and we will use that as an incentive to try and go on an unbeaten run before the international break."
Leicester City manager Nigel Pearson:
"We've started the season OK but performance wise we still have a lot to do.
"We didn't play particularly well today, I think Derby managed the ball very well but ultimately we've come away with the three points. I'm not going to moan too much but we are a lot better than that.
"I look at the positives, it's a clean sheet, we've won, there's room for improvement and it's nice to get two away wins."
Live Text Commentary
Full Time The final whistle goes and the game is over.90:00 +2:46
Free kick taken by Kasper Schmeichel.90:00 +2:41
Conor Sammon is caught offside.90:00 +1:01
Free kick taken by Andy King.90:00 +0:45
Foul by Craig Forsyth on David Nugent, free kick awarded.90:00 +0:05
Martyn Waghorn has an effort at goal and missed to the left of the target.89:55
Anthony Knockaert takes the free kick.89:40
Kieron Freeman booked for unsporting behaviour.89:40 Booking
Foul by Kieron Freeman on Lloyd Dyer, free kick awarded.87:34
Clearance made by Liam Moore.87:30
Lee Grant restarts play with the free kick.87:21
Unfair challenge on Jake Buxton by Martyn Waghorn results in a free kick.86:44
Header at goal by Richard Keogh misses left of the target.86:39
Jamie Ward produces a cross.86:23
Free kick taken by Jamie Ward.85:56
Wes Morgan challenges Chris Martin unfairly and gives away a free kick.83:16
Chris Martin has an effort at goal. Kasper Schmeichel safely holds on.82:53
The ball is sent over by Kieron Freeman.82:31
Headed chance falls to Chris Martin. Kasper Schmeichel safely holds on.
The ball is swung over by Jamie Ward.81:53
Jamie Ward takes a shot.81:48
Will Hughes sends in a cross.78:58 Substitution
Substitution Martyn Waghorn replaces Jamie Vardy.78:49 Substitution
Substitution Conor Sammon on for Johnny Russell.78:28
Lloyd Dyer has an effort at goal and missed to the left of the net.76:50
Clearance made by Craig Forsyth.76:32 Booking
Liam Moore goes into the book for unsporting behaviour.76:03
Will Hughes has an effort at goal and missed to the left of the net.75:07
Will Hughes restarts play with the free kick.75:00
Free kick awarded for a foul by David Nugent on Jamie Ward.74:41
Jamie Ward takes the chance to get an effort at goal. Kasper Schmeichel makes a block.73:12
David Nugent takes the chance to get an effort at goal. Jake Buxton gets a block in.72:46
Danny Drinkwater restarts play with the free kick.72:41
Kieron Freeman gives away a free kick for an unfair challenge on Danny Drinkwater.72:03
Jake Buxton makes a clearance.71:55
Corner taken by Anthony Knockaert from the right by-line.71:45
Clearance made by Richard Keogh.71:19
Jamie Vardy takes a shot. Lee Grant fumbles the ball.71:08
Free kick taken by Kasper Schmeichel.70:48 Substitution
Substitution (Derby) makes a substitution, with Jamie Ward coming on for Paul Coutts.70:38 Substitution
Substitution Lloyd Dyer is brought on as a substitute for Matty James.70:31 Substitution
Substitution Anthony Knockaert on for Chris Wood.70:01
Unfair challenge on Wes Morgan by Chris Martin results in a free kick.69:50
Corner taken by Paul Coutts.69:26
Paul Coutts takes a shot. Blocked by Liam Moore.69:13
Wes Morgan makes a clearance.69:09
Centre by Kieron Freeman.67:17
Corner from the taken by Paul Coutts.66:48
Kieron Freeman takes a shot. Kasper Schmeichel parries the ball away.66:33
Johnny Russell delivers the ball.64:49
Free kick taken by Kasper Schmeichel.64:35
Will Hughes gives away a free kick for an unfair challenge on Danny Drinkwater.62:42
Will Hughes makes a clearance.62:32
Danny Drinkwater takes the free kick.62:19
Craig Bryson challenges Danny Drinkwater unfairly and gives away a free kick.60:28
Danny Drinkwater restarts play with the free kick.60:17
Danny Drinkwater fouled by Will Hughes, the ref awards a free kick.60:04
Kasper Schmeichel takes the free kick.60:02
The official flags Craig Bryson offside.58:57
Shot by Craig Bryson went wide right of the net.58:08
Header by Richard Keogh goes to the left of the goal.57:58
Corner taken by Paul Coutts.56:59
A cross is delivered by Danny Drinkwater.56:02
Clearance made by Liam Moore.55:54
Centre by Paul Coutts.52:50
Will Hughes takes the free kick.52:43
Free kick awarded for a foul by Matty James on Will Hughes.52:17
Will Hughes takes a shot and missed to the left of the goal.52:02
Wes Morgan makes a clearance.51:54
Paul Coutts crosses the ball in from the free kick.51:18
Free kick awarded for an unfair challenge on Paul Coutts by Jeff Schlupp.48:07
Paul Coutts takes the chance to get an effort at goal. Blocked by Andy King.47:39
Clearance by Wes Morgan.46:39
David Nugent takes a shot and went wide right of the net.45:01
The second half kicks off.45:00 +2:44 Half time
Half Time The half-time whistle blows.45:00 +0:17
Clearance by Wes Morgan.45:00 +0:13
Free kick taken by Lee Grant.44:59
Free kick awarded for a foul by Wes Morgan on Richard Keogh.44:51
Clearance by Richard Keogh.44:48
Corner from the left by-line taken by Matty James.42:18
Clearance by Richard Keogh.42:16
Free kick taken by Kasper Schmeichel.41:57
Unfair challenge on Jamie Vardy by Will Hughes results in a free kick.41:44
Clearance made by Wes Morgan.41:41
Corner taken by Paul Coutts.40:13
Jeff Hendrick restarts play with the free kick.40:08
Free kick awarded for an unfair challenge on Richard Keogh by Danny Drinkwater.38:03
Header at goal by Chris Wood goes over the bar.37:53
Matty James takes the free kick.37:45
Craig Forsyth concedes a free kick for a foul on Andy King.37:35
Free kick taken by Craig Forsyth.37:29
Matty James concedes a free kick for a foul on Jeff Hendrick.36:51 Goal scored
Goal! - Lee Grant - Derby 0 - 1 Leicester Lee Grant concedes an unfortunate own goal. Derby 0-1 Leicester.34:05
Corner taken by Matty James.33:22
Clearance by Wes Morgan.33:19
Chris Martin produces a cross.32:55
Kieron Freeman takes the free kick.32:43
Jeff Schlupp concedes a free kick for a foul on Paul Coutts.32:25
Free kick taken by Kasper Schmeichel.32:21
The assistant referee flags for offside against Johnny Russell.32:08
Centre by Craig Forsyth.31:32
Jeff Schlupp restarts play with the free kick.31:23
Jeff Schlupp fouled by Craig Bryson, the ref awards a free kick.29:28
Free kick taken by Lee Grant.29:09
David Nugent gives away a free kick for an unfair challenge on Kieron Freeman.27:49
Craig Forsyth sends in a cross.27:12
Centre by Jeff Schlupp.24:40
Shot by Craig Forsyth.23:58
Craig Forsyth takes the free kick.23:37
Matty James goes into the referee's book.23:37 Booking
Foul by Matty James on Craig Bryson, free kick awarded.20:31
Richard Keogh makes a clearance.20:26
Corner taken by Danny Drinkwater.19:59
Jamie Vardy takes a shot. Lee Grant parries the effort to safety.17:03
Chris Martin takes a shot and goes over the bar.16:55
Clearance by Liam Moore.16:51
Free kick crossed by Craig Forsyth.16:24
Wes Morgan gives away a free kick for an unfair challenge on Chris Martin.13:44
Centre by Paul Coutts.12:52
Clearance by Ritchie De Laet.12:47
Corner from the right by-line taken by Paul Coutts.12:11
Centre by Will Hughes.11:49
Corner from the right by-line taken by Paul Coutts.7:29
Jake Buxton manages to make a clearance.5:16
Chris Wood takes the chance to get an effort at goal. Lee Grant safely holds on.4:32
Craig Bryson takes the chance to get an effort at goal and missed to the right of the target.2:18
Jeff Hendrick takes the free kick.2:10
Free kick awarded for an unfair challenge on Johnny Russell by Wes Morgan.1:31
Clearance made by Wes Morgan.1:10
Corner from the right by-line taken by Paul Coutts.0:00
The match begins.
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