Substitute Ross Barkley scored a dramatic 96th-minute equaliser against Manchester United to maintain our unbeaten start to the season.
The Blues had taken a deserved first-half lead courtesy of a superb Toni Rudiger header, but two Anthony Martial goals after the break had turned the contest on its head, with the three points seemingly headed for Old Trafford.
Maurizio Sarri's side refused to cave in, however, and continued to press for an equaliser, and when David Luiz's header came back off the post right at the death, Barkley was on hand to fire home his second goal in as many matches and secure a hard-fought - but ultimately deserved - point.
Alvaro Morata, scorer of the winning goal in last season’s corresponding fixture, was given the nod to lead the line for the Blues and there was also a return to the side for Mateo Kovacic in midfield, with Barkley making way.
Rudiger was passed fit to play and made his 50th Chelsea start while N’Golo Kante made his 100th Chelsea appearance. Willian and Eden Hazard were tasked with providing the creativity in attack either side of Morata.
There were some familiar faces in the Man United line-up as Nemanja Matic, Juan Mata and Romelu Lukaku all started.
An early opportunity came our way as Kovacic saw his volley from the edge of the box blocked, and just before the 10-minute mark, after Hazard had been tripped right outside the penalty area by his former team-mate Matic, the resulting free-kick was curled over the bar by Willian.
Matic’s foul on Hazard was quickly followed by another, this time deep inside our own half as the Belgian received the ball from Jorginho, earning the Serbian an early yellow card.
United’s first decent chance arrived after 15 minutes when Luke Shaw picked out Lukaku with a cross from the left-hand side, but the striker steered his header well wide from a good position.
Hazard then flashed a delivery across the face of goal after being found by Kovacic, forcing Luke Shaw to concede the corner which led to our opening goal.
Willian’s delivery was superb, the Brazilian hitting the area around the penalty spot, and Rudiger’s execution was even better as the defender arrived unmarked to power his header beyond David de Gea and into the bottom corner.
It was the German’s first goal of the season, and it could scarcely have been timed any better.
Ashley Young followed Matic into the book after clattering Hazard from behind, having already taken the forward out earlier in the game as they challenged for a header, and moments later Rudiger received the same punishment for a foul on Paul Pogba.
Having already given us the lead Rudiger then turned provider as he picked out the run of Marcos Alonso with an incisive pass from deep, although the Spaniard, who had done well to get in behind the United defence, was unable to get the ball under control and it rolled through to De Gea.
It was the Blues seeing far more of the ball as the half wore on, with Jorginho, who had enjoyed a fine first half, almost picking out the run of Willian from the middle of the park as the winger drove into the penalty area at pace.
After falling behind, United had offered little in the way of an attacking threat, and when they did get forward with one potentially dangerous counter attack Pogba’s pull-back was mopped up by the retreating Cesar Azpilicueta.
The Blues, who were unchanged, started the second half posively and went close to extending our lead inside a minute of the restart as Jorginho advanced from deep and found Morata. The striker was unable to take the pass in his stride but did well to get his shot away on the turn, only to be denied by De Gea.
David Luiz threatened soon after when he carried the ball forward, exchanged passes with Hazard and stepped inside the challenge of Chris Smalling, the Brazilian's effort taking a deflection and rolling behind.
Despite that bright opening, however, United were back on level terms nine minutes into the second half.
Kepa had done well to parry away a stinging Mata drive, but as the United man kept it alive and hooked the ball across goal, we failed to clear our lines, leaving Martial with the simple task of finishing from point-blank range to make it 1-1.
Strong, intelligent defending from David Luiz was enough to thwart Lukaku as United looked to hit us on the break, but their leveller had undoubtedly created a more open feel to the game, particularly in comparison to the first half.
David Luiz was in the thick of the action and the defender almost restored our advantage when he headed agonisingly wide from a Willian free-kick.
The game was heating up and Mata was lucky to avoid a straight red card after catching his compatriot Azpilicueta with a late tackle, the attacker escaping with just a booking.
Barkley replaced Kovacic with 22 minutes remaining as Sarri made his first change of the afternoon and moments later De Gea produced a magnificent save to deny Kante, whose powerful drive was heading into the bottom corner.
From their next attack, though, United took the lead. Mata got away down the right-hand side and switch it infield to Rashford, who in turn found Martial. The Frenchman brough the ball under control before clinically dispatching a right-footed strike into the bottom corner.
Hazard saw a strike from inside the box charged down as we attempted to hit back but having taken the lead, United were content to disrupt our rhythm by slowing the game down at every opportunity.
As six minutes of added time were signalled, Pedro and Giroud, both on as subs, almost combined to force an equaliser but as the Frenchman, who was under pressure, met the cross at the near post his effort rolled wide.
The game appeared to be getting away from us, but there was still time for a late twist.
Hazard found Azpilicueta who stood a cross up to the far post where David Luiz crashed a header against the inside of the post, and as the ball landed at the feet of Barkley after De Gea had denied Rudiger, the midfielder gratefully fired the ball into the back of the net to spark jubilant scenes and preserve our unbeaten start to the campaign.
The Blues face another home game in midweek, with BATE Borisov visiting the Bridge in the Europa League, before we travel to Burnley for a Premier League encounter next Sunday.
Chelsea (4-3-3): Kepa; Azpilicueta (c), Rudiger, David Luiz, Alonso; Kante, Jorginho, Kovacic (Barkley 68); Willian (Pedro 74), Morata (Giroud 77), Hazard.
Unused subs: Caballero, Cahill, Zappacosta, Fabregas.
Scorers Rudiger 21, Barkley 90+6
Booked Rudiger 29, Hazard 33
Manchester United (4-2-3-1): De Gea; Young (c), Smalling, Lindelof, Shaw; Pogba, Matic; Rashford (Sanchez 83), Mata (Herrera 74), Martial (Pereira 82); Lukaku.
Unused subs: Romero, Darmian, Bailly, Fred.
Scorers Martial 54 and 73
Booked Matic 12, Young 26, Mata 65, Sanchez 90+3, Pereira 90+5
Referee Mike Dean