Eden Hazard grabbed both goals as Chelsea took an enormous step towards title glory with a 2-1 win over Manchester City.
It was a far from vintage performance from the champions elect, but they held off Pep Guardiola's men, who are now some fourteen points behind the west London club.
Hazard opened the scoring after the returning Vincent Kompany stood too far off him and then saw his Belgium teammate's shot deflect home off his head, but Chelsea hit back immediately when Thibaut Courtois gave away the ball to David Silva, and the Spaniard's shot was tapped home after the rebound.
But Chelsea would take a lead to half-time, and it would stay untouched until the final whistle. Pedro, buccaneering through, was tripped by Fernandinho and Mike Dean could only point to the spot. Hazard saw his first effort saved but reacted smartly to tuck home his second opportunity and lift the roof off Stamford Bridge.
The title party did not start then but it almost can now. Chelsea overcame a big hurdle on their way to Premier League glory, with City once again found wanting.
1. Vincent Kompany’s survives 90 minutes on shaky return
Vincent Kompany’s problems with fitness have transformed the Premier League’s best defender into an afterthought.
He has completed 90 minutes just twice this season, though separated by over four months. After his first full 90, he didn’t play again for nearly a month, when he entered in stoppage time against Everton. He would survive 78 minutes the following week before breaking down at half-time in the Manchester derby and disappearing until late November.
37 minutes at Selhurst Park saw him limp off again, and represented his last appearance until late January when Kompany completed 90 minutes in the FA Cup fourth round tie – also at Selhurst Park.
But injury struck again and, of all the stages to bring him back into the fold, this was one of the biggest for Pep Guardiola to gamble on.
What Pep does with Kompany going forward is very much still a mystery but the following are facts. It has become clear not only that City need to strengthen their central defensive options but that they also can not rely on the Belgian. They must buy a centre-back who can execute a Guardiola gameplan, as they attempted with Aymeric Laporte, and if Kompany can become a factor again then it is a bonus.
But starting him in a game on which City’s season would hinge was bold – even if Aleksandar Kolarov is the alternative.
To blame him for Chelsea's opening goal would be harsh, in terms of the deflection. But he stood off Eden Hazard, marking ghosts, when he should have been shutting his compatriot down.
The bright spot is that he survived the 90 minutes, with City virtually looking to next season already.
2. Jesus Navas struggles out of position
Jesus Navas' start to life as a right-back went... well, much better than you might have expected on Sunday at Arsenal. The Spaniard obviously has the energy and speed required but isn't necessarily the most natural defensive talent.
That said, after giving a good account of himself at the Emirates it was a First Communion of Fire to follow up the weekend's baptism.
Eden Hazard has probably been the best player in the Premier League this season and Navas would much rather have been in that advanced position, running at a fearful novice full-back, than being on the opposite end of things.
In the end, though, that wasn't really Navas' problem. The dinky Spaniard acquitted himself quite well in one-on-one situations but the problem City faced was when he hared up the touchline to join Kevin de Bruyne's pressing. Chelsea's first shot of the day came when Navas had been caught upfield and John Stones was left pointing and screaming at the position where he should have been.
It would happen again and again, eventually resulting in Fernandinho - desperately covering back for his colleague - tripping Pedro in the penalty area and handing Chelsea a second goal before half-time.
As much as Pep seems to love playing players out of position, and as well as Jesus Navas performed at Arsenal, this may not be a long-term or even medium-term fix to another hole that's opened up in City's squad.
3. Goalkeepers continue to baffle this season
Pep Guardiola undoubtedly needs time to drill into a new, unfamiliar set of players exactly what he wants. That is a concession affordable to the former Bayern and Barcelona boss.
It is still, however, entirely fair to call his first season in English football for what it has been - underwhelming.
They still might win the FA Cup but not competing in the Premier League or Champions League is below expectations, especially after spending so much money.
£17million of the huge sum unloaded last summer went on a 33-year-old goalkeeper, Claudio Bravo, who has since been benched. Back-up Willy Caballero could have done better for Chelsea's opener.
As if he was feeling bad for them, Thibaut Courtois dunked his own team into trouble by handing possession to David Silva and gifting City and equaliser, albeit after a rebound.
With Courtois being, ahem, courted by Real Madrid and City's situation in complete flux, both of these clubs could very likely have different men between the sticks at the start of the new campaign. And it's actually a theme at the top of the table, where Liverpool are yet to find their man, Arsenal eventually need a successor for Petr Cech and Manchester United are in a similar situation to Chelsea - thanks to Florentino Perez's wandering eyes.
Stability begins at the back, with the goalkeeper. It is key for the confidence of a back four (or three, in this case) that the man between the sticks is dependable. Both let their sides down today, and there may yet be a price for that.
4. Eden Hazard comes up big when it matters
Hazard was outshone by Wilfried Zaha on this very ground just days ago but, with a potential title on the line, he put in the performance that virtually secured Chelsea the Premier League.
Drifting into a pocket of space to score the first, he only converted the second on the rebound after seeing his penalty saved. He didn't run the game, nor did he create bucketloads of chances.
But he netted twice and became the leading goalscorer against top-six clubs this season. The composure, confidence and ability to get the results in those big games has been a defining characteristic of his campaign.
Now he just needs to explain what on earth he was playing at last season!
5. The title race is done
Tottenham's comeback may give them hope, but Chelsea passed a big test tonight and their lead looks insurmountable.
It is no longer a question of 'if' but 'when' Antonio Conte's side seal a Premier League title, the fruits of his first campaign on English soil.
Whichever way you cut it, Pep Guardiola, Jose Mourinho, Arsene Wenger and Jurgen Klopp have all disappointed this season. Their sides should have been able to challenge.
As it happens, Chelsea have been in a league of their own.