Sunderland came away with a remarkable three points from Stamford Bridge and suddenly resurrected their chances of survival.
The deadlock was broken on 11 minutes when Samuel Eto'o met a Willian corner by taking advantage of some familiar statue-esque defending from Sunderland.
Sunderland responded positively and equalized soon after on 18 minutes. A corner was rolled to Alonso 25 yards out who's shot was fumbled by Mark Schwarzer. Connor Wickham then calmly dinked the ball over the Australian stopper.
The loveable John Terry had the ball in the net a good few seconds after the officials pulled up Matic for a foul on Jack Colback. Though the Sunderland defenders had reacted to the whistle, it was a generous decision. (In Stephen Goldsmith's opinion).
Branislav Ivanovic headed the ball onto the bar via a fumbling Mannone, before Matic and Salah forced him into a double save. The Italian then saved with his feet from Willian and watched on as Seb Larsson muscled Ramires out of what seemed a certain goal.
Either side of the second incident there was some officiating which annoyed both sides. Alonso handballed in the area but could clearly not avoid it, before Ramires bitch-slapped Larsson in the face off the ball. Mike Dean missed that particular one from three yards away.
Chelsea almost opened the scoring early in the second half when Eto'o fired inches wide after a breakaway move. Later, Ba sliced wide from an excellent position after slipping not long after coming on for Oscar.
With ten minutes remaining Jozy Altidore pounced on an Azpilicueta mistake to burst clear and win a questionable penalty. Fabio Borini calmly converted and Sunderland remarkably took the lead.
Schurrie forced Mannonne to tip over from distance, before the host's had another hopeful penalty claim turned down soon after. Terry headed into Vito's hands in injury time with hearts firmly in mouths in the away end.
Substitute Giacherrini fired over from distance as the clock ran down before hashing up a three on one counter attack situation. But it was immaterial as the visitors hung on to become the first EVER side to win a league game at Stamford Bridge under Jose Mourinho.
Chelsea: Schwarzer; Ivanovic, Cahill, Terry, Azpilicueta; Ramires, Matic; Willian, Oscar (BA 59'), Salah (Schurrle 65') ; Eto'o (Torres 74')
Sunderland: Mannone; Vergini, O'Shea, Brown, Alonso; Johnson, Borini, Cattermole, Colback, Larsson (Celustka 90'); Wickham (Altidore 65')