Match ends, Sunderland 0, Leeds United 2.
Leeds maintained their unbeaten start under new boss Thomas Christiansen while inflicting a first loss of the season on Simon Grayson's Sunderland.
The visitors - without their 2016-17 top scorer Chris Wood, who is close to joining Burnley - were clinical on Wearside and deserved their victory.
Samuel Saiz's crisp low finish across goal gave them a 1-0 half-time lead.
Stuart Dallas headed in Saiz's second-half cross to secure the Whites' second league win from their first four games.
Sunderland, who had begun the day level on points with Leeds with five from a possible nine, lacked cutting edge in the final third.
The hosts' best chance came in the first half, as Lewis Grabban's effort was headed off the line and up on to the crossbar by Liam Cooper.
Leeds' victory was their second from two away games this term and came after consecutive goalless draws at home.
Christiansen's side are one of only three teams in the Championship still yet to be defeated, after four games, together with early leaders Cardiff and Ipswich.
Sunderland manager Simon Grayson told BBC Newcastle: "For 20 minutes we were dominant. We asked a lot of questions of them.
"I don't think (Liam) Cooper knew too much about it when it hit him on the head and hit the bar - 70 seconds later it's in the back of our next. Those are the fine margins in a football match.
"From then onwards, I don't think you can fault the players' effort or commitment, but it was just that final ball that really matters, when you're trying to get back in to a game."
Leeds head coach Thomas Christiansen told BBC Radio Leeds: "I don't know if it's the best performance (in my time here so far) but it comes in the best moment, especially when the team needed it.
"We had the circumstances: Barcelona for me, personally, but also for the team, that Chris Wood will leave the team.
"There is no one above Leeds. Everyone worked for the same goal. Today was proof again that we are not winning games because of the individual player, but as the team."
- 23KonéBooked at 69mins
- 15GallowayBooked at 36minsSubstituted forMatthewsat 55'minutes
- 17NdongBooked at 82mins
- 6CattermoleSubstituted forAsoroat 74'minutes
- 9VaughanSubstituted forKhazriat 55'minutes
- 13WiedwaldBooked at 68mins
- 21SáizSubstituted forKlichat 81'minutes
- 19HernándezSubstituted forRoofeat 25'minutes
- 45EkubanSubstituted forDallasat 62'minutes
- Andy Davies
- Shots on Target
Second Half ends, Sunderland 0, Leeds United 2.
Foul by Joel Asoro (Sunderland).
Vurnon Anita (Leeds United) wins a free kick on the left wing.
Attempt missed. Joel Asoro (Sunderland) left footed shot from outside the box is high and wide to the left. Assisted by George Honeyman.
Offside, Sunderland. Jason Steele tries a through ball, but Aiden McGeady is caught offside.
Attempt missed. Billy Jones (Sunderland) right footed shot from the right side of the six yard box is close, but misses to the right. Assisted by Aiden McGeady with a cross.
Attempt missed. Tyias Browning (Sunderland) right footed shot from outside the box is too high. Assisted by George Honeyman.
Attempt blocked. Aiden McGeady (Sunderland) right footed shot from the left side of the box is blocked. Assisted by George Honeyman.
George Honeyman (Sunderland) wins a free kick in the defensive half.
Foul by Mateusz Klich (Leeds United).
Delay over. They are ready to continue.
Delay in match Ezgjan Alioski (Leeds United) because of an injury.
Didier Ndong (Sunderland) is shown the yellow card for a bad foul.
Foul by Didier Ndong (Sunderland).
Ezgjan Alioski (Leeds United) wins a free kick in the defensive half.
Corner, Sunderland. Conceded by Pontus Jansson.
Substitution, Leeds United. Mateusz Klich replaces Samuel Sáiz.
Aiden McGeady (Sunderland) wins a free kick in the attacking half.
Foul by Kalvin Phillips (Leeds United).