The sixth round of Premier League matches was one of the most exciting so far in 2017/18, although in many ways the results unveiled little we didn't already know about the shape of this season. Watford's late victory at Swansea City confirmed they are one of the most interesting teams in England, while performances that typified their respective managers' tactical attitudes saw both Manchester clubs record wins.
Here are three things we learnt from the weekend action:
1) West Ham and Spurs show us there are many different interpretations of the 3-4-3
Although on paper West Ham United and Tottenham Hotspur played with the same formation, in reality they could hardly have been more different, proving that the Premier League's most in-vogue formation is highly versatile and often difficult to interpret before kick-off.
Spurs' Dele Alli consistently made runs ahead of Harry Kane to become a second striker, while Christian Eriksen and Moussa Sissoko played side-by-side ahead of Eric Dier to create a narrow diamond in midfield. Although initially struggling to break through West Ham's narrow formation both of the visitors' first half goals came via Alli's running in behind, and as the match wore on space opened centrally for Eriksen to dominate. Against a three-man defence, Mauricio Pochettino was wise to push Alli into such an advanced position.
Conversely, West Ham essentially played in a flat 3-4-3, with Marko Arnautovic and Michail Antonio pulling very wide either side of Javier Hernandez. This caused plenty of problems on Serge Aurier's side as the Hammers quickly released the ball into the flanks on the counter, successfully exploiting Spurs' high line and Aurier's shaky positional play. The only downside to their system was that it meant they occasionally became overstretched in central midfield, which led to the opening goal and subsequent first-half collapse. There were strengths and weaknesses to both versions of the 3-4-3 on display on Saturday evening.
2) Man City's openness will be punished by better teams than Crystal Palace
It was yet another scintillating attacking display from Manchester City at the Etihad, but Pep Guardiola's team looked very vulnerable defensively and could easily have been 2-0 down before Leroy Sane scored the opener. Better teams, such as their next league opponents Chelsea, will most likely punish their serious flaws.
With David Silva and Kevin de Bruyne roaming from midfield and the full-backs hurtling forward to add width, Fernandinho is often the only player taking up a defensive position in front of City's centre-backs. Consequently, Crystal Palace were able to break quickly in the first half with very simple counter-attacks; Andros Townsend and Christian Benteke peeled wide to split the centre-backs, and Ruben Loftus-Cheek attacked the enormous gap either side of Fernandinho.
Guardiola must find a way to address this issue. One solution would be to instruct Fernandinho to drop right into defence to form a flat and wide back three, or alternatively the Catalan must field an extra deep-lying midfielder to hold back when City are on the attack.
3) Morata gives Chelsea a more direct, counter-attacking option than Costa ever could
After scoring three goals and assisting two more with his head, Alvaro Morata showed an entirely different side of his game on Saturday with an impressive on-the-ground hat-trick. More importantly, the manner of his first two goals showed that he provides Chelsea with a more graceful presence in possession than Diego Costa, which might be better suited to Antonio Conte's counter-attacking football.
Many were confused by Conte's decision to get rid of Costa over the summer, but now we're beginning to see why. Chelsea like to play very aggressive counter-attacking football and with Morata in the side they can feed considerably more passes over the top of the opposition defence. The Spaniard's arrival should see Cesc Fabregas play more cutting through balls - and lead to a more ruthlessly quick Chelsea attack.
Best of the Week – Leroy Sane
Man City's German winger has improved dramatically under Guardiola and is now one of the brightest young prospects in European football. Sane's burgeoning relationship with David Silva is particularly impressive; their partnership is currently the most fruitful in the Premier League.
Sane understands the tactical side of the game like few others of his age. Guardiola splits the pitch into vertical columns and instructs his players to alternate positions with their team-mates to ensure they never occupy the same zones, and Sane is currently the best winger at following these rules. His out-to-in runs are perfectly timed for Silva's clipped through balls, but equally important are his movements between the lines that drag defenders away and create space for others.
Worst of the Week – Simon Mignolet
Despite saving a poor Jamie Vardy penalty, Simon Mignolet showed once again why he is not good enough to play for a side hoping to challenge for the Premier League title. Both Leicester goals came after mistakes from the Belgian, and he conceded the penalty that should have seen the Foxes pull level. Loris Karius simply has to be starting more regularly.