Chelsea saw off a spirited Sunderland side to claim a ninth win in 12 matches and keep their title bid on track thanks to John Terry's towering header.
Terry's goal was his first for Chelsea since August 2006
Terry met Frank Lampard's corner and forced the ball home at the near post for his first Blues goal in 19 months.
But it was the Black Cats who had the best chances after the opening quarter.
Blues keeper Carlo Cudicini made a superb stop to keep out Andy Reid's curling free-kick and Kenwyne Jones missed a glorious close-range header.
Sunderland will consider themselves very unlucky after a battling display which saw them force Chelsea on to the back foot for much of the second period.
It's not often that you are applauded off after a defeat but the players were very, very good
But their impressive second-half showing looked unlikely as Avram Grant's side took control early on.
After a decent spell of pressure, the visitors took the lead when Terry headed home Lampard's vicious inswinging corner.
The Blues skipper escaped the attentions of marker Jones to meet the ball at full tilt at the near post, and power it past Craig Gordon.
Amazingly, it was the skipper's first goal since the opening day of last season and was no more than the visitors deserved for their early dominance.
The lively Salomon Kalou and excellent Joe Cole were both enjoying plenty of freedom out wide as the Blues forced five corners in the opening 15 minutes.
Kalou twice almost got in on goal while a superb last-ditch block tackle by Phil Bardsley denied the Ivorian his second goal in two games.
And a wonderful one-two between Ashley Cole and Lampard almost saw the former tee up namesake Joe to slide in a second.
Cudicini (l) and O'Donovan almost come to blows
But Sunderland, prompted by the impressive if slightly rotund Andy Reid in midfield, started to settle.
Roy O'Donovan's pace was posing plenty of problems and Jones was a constant menace in the air.
Chelsea looked far from convincing at the back and were missing the organisational skills of the influential Ricardo Carvalho.
Edwards blazed over after good work by Reid and the Irishman almost levelled the scores with a sweet 25-yard free-kick just before the half-hour mark but was denied by a superb Cudicini save.
O'Donovan also had a header comfortably saved by the Italian and the pair clashed again soon after when Cudicini reacted furiously after O'Donovan flicked out a leg and connected with the keeper as he slid in to collect a through-ball.
At the other end, Gordon made a fine save from Lampard after an intricate passing move and the frenetic pace continued after the break with Sunderland on top.
Alex made a mess of a clearance but Reid badly sliced his attempted follow-up.
Cudicini then palmed Grant Leadbitter's long-range effort away for a corner and from the resulting set-piece Danny Collins outmuscled Terry but his header went wide.
Jon Obi Mikel almost deflected Dean Whitehead's near-post cross past Cudicini but the home side's best chances fell to Jones.
Substitute Dwight Yorke was allowed time on the left and his flighted cross found the big striker but Jones wastefully headed the ball straight at Cudicini from six yards.
And in the final five minutes another Yorke cross saw Jones head over while Leadbitter dragged an injury-time effort narrowly wide.
Sunderland manager Roy Keane:
"I thought it was real top quality performance, the effort and intensity of our play was excellent and we created chances.
"Against a top quality team we were outstanding. I could not have asked any more from the players.
"It's not often that you are applauded off after a defeat but the players were very, very good and gave everything."
• Chelsea manager Avram Grant:
"It was very difficult. They fought for their lives and fought for every ball. They pressed well and played good.
"The first 30 minutes we played very well and dominated the game and could have scored more.
"After that it was not so easy and it became a battle but we defended well and we won. They are a good team and will take a lot of points here."
Sunderland: Gordon, Bardsley, Evans, Nosworthy, Collins, Edwards (Prica 62), O'Donovan (Yorke 73), Whitehead, Leadbitter (Harte 85), Reid, Jones.
Subs Not Used: Fulop, McShane.
Chelsea: Cudicini, Ferreira, Alex, Terry, Ashley Cole, Obi, Ballack (Essien 73), Lampard, Joe Cole (Wright-Phillips 82), Kalou, Drogba.
Subs Not Used: Hilario, Carvalho, Shevchenko.
Goals: Terry 10.
Ref: Mike Dean (Wirral).
BBC Sport Player Rater man of the match: Chelsea's John Terry 8.68 (on 90 minutes).
• Please note that you can still give the players marks out of 10 on BBC Sport's Player Rater after the match has finished.