Maurizio Sarri’s position as Chelsea head coach was strengthened by a 2-0 win which featured a Willy Caballero clean sheet and a Tottenham defensive howler.
Under-fire Sarri belatedly exerted his authority by dropping Kepa Arrizabalaga for his refusal to be substituted in Sunday’s Carabao Cup final penalty shootout loss to Manchester City.
The world’s most expensive goalkeeper was replaced by Caballero as Pedro’s 57th-minute strike was followed by an embarrassing Kieran Trippier own goal.
The right-back passed the ball by Hugo Lloris into his own net after 84 minutes as Spurs slipped to a fourth successive away loss.
They will now be looking over their shoulders, with Arsenal, Manchester United and Chelsea closing in, after slipping nine points off leaders Liverpool in the title race.
Great night for Sarri
Forget any of the men in blue, the man that deserved all the credit tonight was the Chelsea head coach on the sidelines.
Few have been under as much pressure as the 60-year-old over recent weeks and he went into this game knowing that defeat could be the end of his Chelsea career.
But having shown signs of encouragement, albeit in a losing cause, in the EFL Cup Final on Sunday, this was a hugely significant triumph for Sarri’s side.
The Chelsea players fought for one another and perhaps showed that they’re playing for their manager too.
You could argue Sarri got his team selection spot on, especially having secured a 2-0 victory, but it was such a crucial result given top four rivals Arsenal and Manchester United also won.
Chelsea don’t play another member of the top six until April 14th and have five League games to try and climb out of sixth spot before then.
Sarri looked doomed after losing to Manchester United last week and he still has a lot to prove to stay in the job, but finally there are reasons to be optimistic.
Caballero has a quiet night as Kepa looks on
Before a ball was kicked, everyone was keeping an eye on the team sheet to see who would start in Chelsea’s goal.
Would Kepa pay a heavy price, on top of the fine, for his act of insubordination at Wembley or keep his place between the posts?
Chelsea managed to keep the decision under wraps until just before 7pm when news leaked out that back-up keeper Willy Caballero had got the nod.
Sarri said he wanted to send a message and this was certainly a strong one. The only way it would be proven right was the final scoreline.
As it turned out, Caballero watched almost as much of the game as Kepa was forced to do sitting on the bench.
Tottenham huffed and puffed but only a superb dipping shot from Harry Winks that hit the bar troubled the veteran.
The question will be now whether this is just a one-off or will Kepa return to face Fulham on Sunday.
Given the way Caballero calmly collected cross after cross and oozed composure, there is a chance that Kepa will have to wait a bit longer to play for Chelsea again. Some would say it serves him right.
A reminder of Pedro’s quality
The former Barcelona star has not had the best of periods lately and looked very much on the wane.
Even for nearly an hour of this crucial derby, Pedro wasn’t carrying much of a threat on the right hand side and seemed to be frustrating the home crowd.
It felt like he was about to be replaced by Willian only for him to show trademark silky composure in the area to put Chelsea in front.
It might have been the plan all along, but Eden Hazard was the one to make way after that instead.
Toby Alderweireld was completely dumbfounded as he turned inside before drilling a shot through Hugo Lloris’s legs.
Just as impressive was what came soon after in his own area, winning a crucial tackle before dribbling majestically clear past a few men in white shirts.
Suddenly the crowd were singing his name again and this was one Spaniard who really had done something for the cause this week.
Higuain failing to make the impact Chelsea needed
Sarri battled for six months to sign the Argentina striker but he has yet to show that the fight was worth winning.
This was Higuain’s seventh appearance for the Blues since joining on loan from AC Milan in January and he has scored in just one of them – a fine brace against bottom of the table Huddersfield.
After seeing Alvaro Morata struggle for 18 months, Chelsea were desperately hoping Higuain would make the same contribution for Sarri as he did when playing under the Italian at Napoli.
There have been examples of fine running off the ball and hold up play, but not enough to make the difference.
Tonight was a real example of Higuain fluffing his lines. In the opening 20 minutes he could have got Chelsea off to the perfect start, but mishit one shot off the post and curled another past the post.
There were other occasions where he looked every one of his 31-years-of age because he was so slow.
Chelsea had been considering a younger, unproven man in Krzysztof Piatek and he ended up being Higuain’s replacement at the San Siro. Perhaps the Blues are regretting it now that Piatek has already scored seven times for the Serie A side.