Brighton struck twice in second-half stoppage-time as 10-man Chelsea threw away the lead to slump to a 3-1 Premier League defeat at Stamford Bridge.
Maxim De Cuyper's header put Brighton into the lead at the start of 11 added minutes at the end of the match to stun the home side, who had laboured ever since the dismissal in the 53rd minute of Trevoh Chalobah.
Substitute De Cuyper was left unmarked to nod the ball home after Mats Weiffer had turned Yasin Ayari's deep cross back into the box, before fellow substitute Danny Welbeck added a third - his second - to finish Chelsea off.
For the second time in as many league matches, Enzo Maresca had been left looking for answers following a red card.
This time he at least had the comfort of an advantage given to his side by Enzo Fernandez's header midway through the first half, but after Chalobah was sent off for denying Diego Gomez when through on goal - as at Old Trafford last weekend - Chelsea were made to improvise.
That they failed to do so raised questions again about this young side's ability to guile and organisational nous when under pressure.
Two Maxime Esteve own goals and a late Erling Haaland brace helped Manchester City beat Burnley 5-1 in the Premier League to make it 14 wins in a row over the Clarets.
After all the talk about Kyle Walker's return to the Etihad Stadium in the build-up to this game it was City's starting right-back Matheus Nunes who scored their key second goal, rifling in a 61st-minute volley to restore their lead after Jaidon Anthony cancelled out an early opener off Esteve.
Four minutes later the unfortunate Esteve inadvertently turned in Oscar Bobb's shot to effectively settle what had become a nervy game for City before two goals in four minutes from Haaland added some gloss to the scoreline.
Omar Alderete's first-half header helped Sunderland clinch their first away win of the season with a 1-0 victory over Nottingham Forest in Ange Postecoglou's first home game in charge.
Defeat left Postecoglou still waiting for his first success since taking over as Forest boss. They are now without a win since the opening day, while Regis Le Bris saw his side climb into the Champions League places with their third win of the campaign.
The first half lacked real quality but a contentious moment allowed Sunderland to make the decisive breakthrough as Alderete notched his first for the club after Nicolas Dominguez was booked for a debatable simulation decision outside his own area.
Forest failed to have a shot on target in the first half but it was a completely different story after the break as Black Cats goalkeeper Robin Roefs made six saves to ensure Sunderland picked up the three points.
Postecoglou has not delivered a win in his opening five games and a return to their home patch resulted in Forest's third loss of the campaign, although the Australian may feel hard one by with this one.
Eli Kroupi struck a stoppage-time equaliser to rescue Bournemouth a point in a 2-2 draw at Leeds.
Sean Longstaff's first Leeds goal appeared to have sealed them back-to-back wins as they hit back to lead 2-1, but substitute Kroupi volleyed home at the far post in the third minute of added time to deny Daniel Farke's side victory.
Summer signing Longstaff had volleyed Leeds in front early in the second half after Joe Rodon's header before the interval had cancelled out Antoine Semenyo's opener.
Leeds, who presented one of their all-time greats, Republic of Ireland legend, John Giles, with a lifetime achievement award before kick-off, extended their unbeaten run at Elland Road to 23 league matches, stretching back over a year.
