Match ends, Sheffield United 0, Leeds United 1.
Patrick Bamford's late header earned Leeds United a hard-fought victory over Sheffield United, who are still searching for their first points of the season.
After both goalkeepers excelled, it looked as though a first Premier League derby between the two Yorkshire sides in 26 years was heading for a goalless draw.
But with two minutes remaining, Bamford rose at the back post to meet Jack Harrison's cross and head in his third goal of the season to send Leeds' players and staff wild.
It was just reward for a second half in which Leeds continued to ask questions of home keeper Aaron Ramsdale.
Sheffield United, who have never previously failed to score in their opening three league fixtures, will regret John Lundstram's first-half shot being superbly saved by Illan Meslier.
But a second win of the season for Leeds, and a clean sheet, having conceded seven goals in their opening two games, will be relished by their fans - especially against one of their fiercest rivals.
Meslier lays groundwork for Leeds victory
Leeds have enjoyed an entertaining start to the season, having scored and conceded seven goals in their opening two fixtures against Liverpool and Fulham.
The fact they pushed the champions close in a 4-3 loss at Anfield and held out to beat Fulham by the same scoreline suggests they will win many new fans this campaign.
But against Sheffield United they showed they could grind out a victory and were thankful to Frenchman Meslier, who excelled in goal.
In thwarting Lundstram from eight yards, he pulled off one of the saves of the season so far. He also denied George Baldock with another superb effort.
Led superbly by midfielder Kalvin Phillips - a timely performance, with England manager Gareth Southgate watching - Marcelo Bielsa's side created plenty of chances themselves in a finely-balanced game.
But they could not find their way past Ramsdale, who denied Luke Ayling and Stuart Dallas' toe-poke in the first half before other efforts from Helder Costa and Bamford after the break.
When Dallas finally rounded Ramsdale from Ayling's long through-ball, Chris Basham cleared his tame effort off the line.
But Leeds finally found a way through in the 88th minute as Bamford nodded in a downward header to clinch three points.
Blades paying for lack of punch up front
Wilder will feel like misfortune is becoming too common a companion for his side, who unexpectedly finished ninth last season after their return to the Premier League following a 12-year hiatus.
Having lost to Wolves in their opening game, they also lost John Egan to a contested red card in the defeat by Aston Villa - although Ethan Ampadu was an able deputy here - and Wilder said before kick-off that defender Jack O'Connell would need surgery on an injured knee.
But for a team built on a solid defence, their big problem is the lack of goals, an issue that has been underlined this season.
They had the chances to score and having weathered an early Leeds onslaught, finished the first half on top.
Lundstram, who was a key scorer for the Blades in the first half of last season, should have beaten Meslier after David McGoldrick's clever flick from Ben Osborn's cross.
Five minutes before half-time the Leeds keeper showed his class again with a fine save from Baldock's rising drive and Enda Stevens could not find a way through in the second half.
But it was a barren day for Blades front pair of Oli Burke and McGoldrick, who did not have a shot on target between them.
As they pressed for a winner, with substitute Billy Sharp aiming to score against his former team, they began to leave gaps at the back which Leeds exploited.
Defeat leaves Wilder's team at the bottom of the table and their task is not set to get any easier with Arsenal, Liverpool and Manchester City all to come next month.
'It's not going our way' - what the managers said
Sheffield United manager Chris Wilder told BBC Sport: "They are a decent team, a high energy, high tempo side and I thought we matched that. It's all about creating chances and putting them in the back of the net. We did the first bit but couldn't do the second bit.
"It's not going our way at the moment but it is a time to stand up stick your chest out and show what you are about in a lot of ways. Bravery in and out of possession, brave as a team. We have enough characters in there. It was a really tight game and the players will be thinking it's one that has got away."
Leeds manager Marcelo Bielsa said: "I have already experienced a Yorkshire derby in the Championship but it is different in the Premier League. When there are no fans it is hard to compare. The games are very competitive and it is hard to impose yourself. The difference between the two teams was not a lot."
On suggestions Patrick Bamford might struggle in the Premier League, he added: "There are a lot of people who thought contrary to what you say. The league season is very long. Hopefully he can continue to show his obvious qualities."
Blades' worst run since 2013 - the stats
- Sheffield United have lost their opening three league matches of a season for only the third time, also doing so in 1966-67 and 1995-96.
- Sheffield United have lost their past six league matches, their worst run since September 2013 (also six in a row).
- Leeds have won 14 of their past 17 league matches, keeping clean sheets in 11 of those wins.
- Bamford is the first player in Leeds' history to score in his first three top-flight appearances for the club.
- The Leeds striker became the first player since Mick Jones in the 1968-69 season to score in Leeds' first three matches of a top-flight season.
- Bamford is only the third player to score on matchday one, two and three of a Premier League season for a newly promoted team.
Leeds welcome Manchester City to Elland Road on Saturday (17:30 BST), while Sheffield United travel to Arsenal on Sunday (12:00).
- 2BaldockBooked at 67mins
- 7LundstramBooked at 58minsSubstituted forNorwoodat 64'minutes
- 17McGoldrickSubstituted forMcBurnieat 74'minutes
- 14BurkeSubstituted forSharpat 74'minutes
- 23PhillipsBooked at 6mins
- 17Hélder CostaSubstituted forPoveda-Ocampoat 66'minutes
- 11RobertsSubstituted forRodrigoat 45'minutesSubstituted forAlioskiat 90+1'minutes
- Paul Tierney
- Shots on Target
Second Half ends, Sheffield United 0, Leeds United 1.
Liam Cooper (Leeds United) wins a free kick in the defensive half.
Foul by Oliver McBurnie (Sheffield United).
Corner, Leeds United. Conceded by George Baldock.
Substitution, Leeds United. Ezgjan Alioski replaces Rodrigo Moreno.
Corner, Leeds United. Conceded by Ethan Ampadu.
Goal! Sheffield United 0, Leeds United 1. Patrick Bamford (Leeds United) header from the centre of the box to the bottom left corner. Assisted by Jack Harrison with a cross.
Attempt saved. Billy Sharp (Sheffield United) left footed shot from the left side of the box is saved in the centre of the goal. Assisted by Aaron Ramsdale.
Attempt saved. Stuart Dallas (Leeds United) right footed shot from outside the box is saved in the centre of the goal. Assisted by Jack Harrison.
Illan Meslier (Leeds United) wins a free kick in the defensive half.
Foul by George Baldock (Sheffield United).
Attempt missed. Jack Robinson (Sheffield United) right footed shot from very close range is close, but misses to the left. Assisted by Ben Osborn with a cross following a corner.
Corner, Sheffield United. Conceded by Kalvin Phillips.
Attempt blocked. George Baldock (Sheffield United) left footed shot from outside the box is blocked. Assisted by Sander Berge.
Offside, Leeds United. Robin Koch tries a through ball, but Patrick Bamford is caught offside.
Corner, Leeds United. Conceded by Aaron Ramsdale.
Attempt saved. Ian Poveda-Ocampo (Leeds United) left footed shot from outside the box is saved in the top left corner. Assisted by Patrick Bamford.
Corner, Sheffield United. Conceded by Luke Ayling.
Stuart Dallas (Leeds United) wins a free kick in the defensive half.