Chelsea surely cannot be caught now.
An emphatic win over Arsenal has ended Arsene Wenger's hopes of winning the Premier League title, and such a typically gutless display from the Gunners may have all-but ended his tenure as manager. The case for a new contract for the Frenchman is becoming weaker and weaker.
Liverpool's 2-0 loss to Hull City should not have surprised anyone given the contrasting fortunes of Marco Silva and Jurgen Klopp, while big wins for Manchester United, Everton, and Sunderland plunged their opponents into serious trouble.
Here are three things we learnt from the weekend action:
1) Guardiola's system makes sense again thanks to energetic Gabriel Jesus
The complexity of Pep Guardiola's tactical strategy has been undermined by the clunky, confidence-stricken performances of his players, but we were reminded of his astute positional coaching against Swansea City on Sunday afternoon.
Fernandinho's return to the side certainly helped, but the main reason for their sudden resurgence was 19-year-old Gabriel Jesus.
Pep teams maximise space by constantly shifting between the lines, creating multiple passing triangles in all areas of the pitch and utilising the half-spaces as often as they can. This was possible against Swansea because Guardiola used two very wide wingers (Leroy Sane and Raheem Sterling stretching the pitch) and let two playmakers (David Silva and Kevin De Bruyne) roam into the half-space columns, safe in the knowledge that Fernandinho (playing right-back) could shift across to support Yaya Toure in defensive midfield.
However, this still would not have been successful without Jesus, the scurrying nuisance acting as leader of the counter-press and chief disorganiser of the opposition.
His darts and shimmies caused chaos, turning City's patient, triangular build-up play into meaningful and direct movement in the final third. It was Jesus' intelligence that allowed the likes of De Bruyne and Sane to make unnoticed diagonal runs behind the defence; he is the type of menacing forward who, like Luis Suarez or Alexis Sanchez, raises the energy levels of those around him.
2) Klopp must find a new tactic to break down stubborn defences
Only teams in the bottom half of the Premier League or in the Championship have beaten Liverpool this season, which is not a coincidence.
Like Burnley, Swansea, and Wolverhampton Wanderers, Hull triumphed by sitting deep and absorbing pressure. Jurgen Klopp is yet to work out how to react to this.
Liverpool were too narrow on Saturday. Klopp loves to create high-tempo short-passing options in central areas (where there are 360 degree passing lines), and so instructs his playmakers/forwards to bunch together.
This system cannot work against compact and hard-working opponents like Hull, who simply squeezed out space whenever red bodies approached the box (Marco Silva's back four made 46 clearances between them).
The answer is to quickly switch the play from flank to flank with long diagonals, which stretches the shell apart, tires out the opponent, and isolates full-backs one-on-one with your sharpest wingers.
Sadio Mane and Philippe Coutinho should be hugging the touchline in games like this, but instead they floated around in the most congested areas. Klopp has a lot of thinking to do.
3) Wenger's wayward full-backs suggest his players have run out of ideas
Initially, Wenger's unexpected 4-3-3 formation caused Chelsea problems, largely because Mesut Ozil found space on the left flank and Alex Iwobi's energy helped make like tough for Nemanja Matic and N'Golo Kante.
However, the visitors' dominance didn't last long, leaving us once again with an agonising sense of déjà vu.
The opening goal summarised Arsenal's lack of strength, desire, and aggressiveness; Gary Neville correctly pointed out that Wenger's team rarely confront the opposition, instead allowing them to pass through their lines of defence with relative ease. Theo Walcott's disinterest in tracking Marcus Alonso ahead of the opening goal typified the club's attitude.
But more worrying was Gabriel's and Nacho Monreal's gung-ho approach - an outrageous tactical error. The most obvious features of Chelsea's counter-attacking this season has been Eden Hazard's hovering position high on the left flank, and so to leave him alone – as Arsenal did countless times in this match – made no sense.
Leaving Hazard in a 30-yard bubble of space was costly, not because it directly led to goals but because it set the tone of a game that gradually slipped away from the Gunners.
Either Wenger showed great tactical naivety or his players simply did not listen to his instructions. It's hard to say which explanation is the more alarming.
Best of the Week – Romelu Lukaku
For 90 minutes on Saturday, Romelu Lukaku was the best player in the world. Every touch was perfect and every shot flew into the net, suggesting that the Belgian – still only 23-years-old – could become the frontman for one of Europe's biggest clubs.
His intelligence and off-the-ball running have improved dramatically since Roberto Martinez left the club, while Ronald Koeman's more direct strategy is better suited to Lukaku's strengths.
A transfer next summer to one of the current top four is likely.
Worst of the Week – Southampton's defence
Jose Fonte's move to West Ham United was a major blow for Claude Puel, and his defensive woes were exacerbated when Virgil van Dijk's ankle injury proved worse than first feared.
Unsurprisingly, Saints' makeshift duo of Jack Stephens and Maya Yoshida were picked apart by the Hammers.
The opening goal saw the pair split by a simple through ball - as Andy Carroll somehow outpaced Stephens before slotting past Fraser Forster - and West Ham's third resulted from a free-kick, after Oriol Romeu fouled as he scrambled to cover a gap. Another eight weeks without van Dijk could see Southampton dragged into a relegation battle.
