Two late goals cruelly denied 10-man Southampton a point at Stamford Bridge, as Saints once again made life difficult for a team with genuine title aspirations.
Having held both Manchester clubs to draws already this season, Saints were only six minutes away from repeating the trick at the home of the Champions League holders.
But the dismissal of goalscorer James Ward-Prowse, whose second-half penalty had cancelled out Trevor Chalobah’s early opener, led to a backs-to-the-wall finale.
Chelsea took full advantage as Timo Werner tapped in, before Ben Chilwell’s half-volley was adjudged to have crossed the line before Alex McCarthy could intervene.
Ralph Hasenhüttl made two changes to his starting line-up, as Theo Walcott and Nathan Tella returned after extended periods out of the side.
Walcott was back after more than a month out injured, while Tella was making his first Premier League start of the season having not featured in the league at all since a 10-minute cameo on the opening day.
Stuart Armstrong, who had not kicked a ball all season, was fit enough for the bench, but Chelsea loanee Armando Broja was ineligible against his parent club.
Saints started with a spring in their step, armed with four attacking players boasting raw speed, and their pressing from the front almost caused a problem for Édouard Mendy, who dallied on the ball and nearly paid the price.
But Chelsea are a team with real firepower, and took only four minutes to test McCarthy when César Azpilicueta fed Werner, who forced the keeper to spread himself effectively.
It would prove only a temporary stay of execution for Saints, who were soon trailing when Chilwell’s corner was flicked on by Ruben Loftus-Cheek and converted at the far post by the flying figure of Chalobah.
Saints might have been undone from another corner from the same side when Antonio Rüdiger headed over, but responded well with a couple of close shaves around the midpoint in the half.
Adam Armstrong kept Mendy busy with a low shot from 20 yards that took a slight deflection en route to the Chelsea stopper, who was beaten all ends up by a fierce half-volley from similar range by Ward-Prowse that fizzed just past the post.
The Chelsea reply was a thunderous volley from Loftus-Cheek that had McCarthy leaping to his left, relieved to see the ball fly wide.
Then Chilwell traded passes with Mateo Kovačić and ensured McCarthy was tested, as the keeper stuck out a foot to keep the Blues at bay.
Chances were always going to be hard to come by at the home of the European champions, and Hasenhüttl was visibly frustrated when Walcott could not hit the target when he threw himself at a teasing cross from Kyle Walker-Peters after some neat footwork from the full-back.
Chelsea had the ball in the net again nine minutes before the interval, when the previously well-marshalled Romelu Lukaku steered in Rüdiger’s defence-splitting pass, but the striker had made his move fractionally early and was flagged offside.
Saints needed some last-ditch defending to keep themselves within striking distance, as Oriol Romeu threw himself in the way of Werner’s shot before Tino Livramento got back at former teammate Callum Hudson-Odoi with a superb sliding challenge.
Hudson-Odoi thought he’d provided an assist for Werner, with Saints now hanging on, but an earlier foul by Azpilicueta on Walker-Peters was deemed sufficient for the goal to be ruled out after referee Martin Atkinson consulted the pitchside monitor.
When a replay was shown on the big screens inside the stadium, the home supporters were incensed and manager Thomas Tuchel was booked for his protestations.
Whilst the decision was a soft one, Walker-Peters was certainly impeded from behind by the Chelsea skipper, who only reclaimed possession as a result of upending the Saints left-back.
Still in the game at 1-0, Saints made a change at the break, sacrificing Walcott to bring on Ibrahima Diallo and moving Romeu back into the heart of a three-man defence, matching up Chelsea’s system.
That tactical tweak certainly helped to scupper Chelsea’s momentum. Half time had come at a good time for Saints, who were suddenly growing in confidence.
This gradually growing momentum led to a moment of elation for the 3,000 away fans, who were roaring themselves hoarse in one corner of Stamford Bridge.
After Diallo spread the ball to the right, Livramento attacked Chilwell, darting inside and then quickly changing direction – too quickly for the England international, who lunged in late and sent the teenager crashing to earth for a clear penalty.
Up stepped Ward-Prowse who made no mistake, gleefully dispatching the spot-kick in familiar fashion, low into his favourite corner as Mendy chose wrong in diving to his left.
With 20 minutes to go Saints were on course for a very valuable point, but Lukaku’s strength in holding off Mohammed Salisu and cleverness to spot Werner presented a chance for the German, who jinked past Walker-Peters but could not beat McCarthy, who saved brilliantly with a giant left hand.
Having been knocked off the top by Manchester City last time out in the Premier League and defeated in the Champions League by Juventus in midweek, Chelsea were desperate to return to winning ways and Saints’ job was about to get tougher with the dismissal of their captain 13 minutes from time.
With the hosts patiently building an attack from deep, Ward-Prowse sensed a chance to nick possession on the edge of the box and slid in on Jorginho, who just managed to release the ball before he arrived.
Initially booked for the tackle, Ward-Prowse’s luck was out when Atkinson was again sent to consult the monitor and decided the incident was worthy of a harsher punishment, as yellow turned to red and Saints were down to 10.
Whilst the challenge did not look good in slow motion, it was only the incentive of winning the ball so high up the pitch that tempted Ward-Prowse to throw himself into it.
The pressure on the visitors was bound to be taken up a notch, and Chelsea finally had their second goal six minutes from time when Werner poached to tap in Azpilicueta’s low ball across the six-yard box.
When Lukaku and Azpilicueta both missed gilt-edged chances to add a third, Chilwell connected sweetly with the loose ball to complete the scoring.
It was harsh on Saints, who had once again performed admirably against a member of the Premier League’s established elite.