Across Europe's top leagues several sides have made unbeaten starts to the season, allowing them to race clear of domestic rivals and assume the role of early title favourites.
ESPN FC asked club correspondents from Napoli, Barcelona, Manchester United, Manchester City, Borussia Dortmund, Paris Saint-Germain, Juventus and Inter Milan to identify the defining factor in their strong start to the campaign.
BARCELONA: (WWWWWWW) - Teamwork
There have been three key factors to Barcelona's perfect start to the season. The first has been Lionel Messi. In seven league games he has scored 11 goals, including four in one game against Eibar. The second factor has been Ernesto Valverde's insistence on the team playing as one.
The one complaint about playing with a Messi, Neymar and Luis Suarez frontline was it often left Barca outnumbered in defence. With Neymar gone, Valverde has been able to shift the focus slightly back on to the midfield, which has helped in defensive transitions -- Barca have only conceded twice in the league. Finally, it has to be noted they have had seven very winnable games. Although, admittedly, it was slipping up in those type of fixtures that cost them the title last season. -- Sam Marsden
Who's next? Atletico Madrid, Malaga, Athletic Bilbao
NAPOLI: (WWWWWWW) - Consistency
Lorenzo Insigne hit the nail on the head as to why Napoli have won their first seven games of the season: "We remained united and stuck together," he said. It may sound convoluted, but changing nothing has changed everything for the Azzurri. Runners-up behind Juventus last season, Napoli did not seek big-name summer signings to bridge the gap to the Bianconeri, instead they let the technical and tactical revolution instigated by Maurizio Sarri two years ago run its natural course.
Already in the round-of-16 Champions League defeat to Real Madrid last season, there were many glimpses of the quality that Napoli have; it just needed refining. The best way to do that is not to change the tools, but to sharpen them and make them even more effective and, perhaps more pertinently, consistently reliable.
"The fact we can play together with our eyes closed and that we're a great bunch of lads who decided to stick together is certainly an advantage," Insigne added. -- Ben Gladwell
Who's next? Roma, Inter, Genoa
MAN UNITED: (WWWDWWW) - Goals and style
Jose Mourinho has bristled at suggestions Manchester United's good start has been made possible by a favourable schedule, but it has helped that they have only faced two teams who finished in the top half of the Premier League last season. That said, you can only beat the teams put in front of you and United have, for the most part, done it in style.
The biggest factor has been goals. They have got a good defensive record, conceding just twice so far, but they were good defensively last season, too. The problem then was at the other end. But that hasn't been an issue this time around United have scored 21 league goals in just seven games and scored four in a game four times already. -- Rob Dawson
Who's next? Liverpool, Huddersfield, Tottenham
MAN CITY: (WDWWWWW) - Defensive solidity
In a thrilling start to the season, where Manchester City have already scored 30 goals in just 10 games, it's actually at the other end of the pitch where Pep Guardiola's side have made the biggest improvement. City have kept seven clean sheets and conceded just three times. Last season, ignoring the Champions League qualifiers against Steaua Bucharest, City kept just two clean sheets from their first 10 games and conceded 11 times. That improvement starts right at the back with new goalkeeper Ederson, who has shown assurance and confidence with his shot-stopping and command of his area.
It has transmitted forward to his central defenders in front of him where John Stones and Nicolas Otamendi have looked vastly more solid flanked by a notable enhancement in the full-backs that Guardiola brought in during the summer. It has given a base for City to dominate every game they've played and unleash their merciless attacking style. -- Jonathan Smith
Who's next? Stoke, Burnley, West Brom
BORUSSIA DORTMUND: (WWDWWWW) A long-term approach
Coming out of a difficult first half of 2017, Dortmund remained calm amid the storm of Thomas Tuchel's exit. While it took them some time to appoint Peter Bosz as their new head coach, the club's superordinate transfer philosophy allowed them to bring in new signings regardless.
Over recent years, they have excelled in taking young players to the next level. BVB do not belong to that group, and they are aware it will take time. Die Schwarzgelben also profited from having a plan B in store when they brokered Ousmane Dembele's Bundesliga record transfer to Barcelona. Dynamo Kiev's Andriy Yarmolenko needed a transition period to adjust to life in Germany, and his physicality has brought a new depth to Dortmund's attacking game.
While still vulnerable in defence, BVB's attacking power has been superior in Bundesliga, and kept the ball in the opponent's half for the majority of the domestic games. Flying high, Dortmund will face a stern test against RB Leipzig following the international break. -- Stephan Uersfeld
Who's next? Leipzig, Frankfurt, Hannover
PSG: (WWWWWWDW) - Big-spending pays off
Paris Saint-Germain have been motivated by a desire to reclaim the Ligue 1 title from Monaco. While Unai Emery's men have only conceded five goals in Ligue 1 so far, they have also scored 27 in that time with the star trio Kylian Mbappe, Edinson Cavani and Neymar, otherwise known as "MCN", accounting for 16 of those 27 goals.
Although the France and Uruguay internationals were unable to prevent a recent goalless draw in Montpellier, PSG have otherwise been insatiable in front of goal this term. It is this newly discovered ruthless streak in attack that has helped them make such a strong start to this season because, for the most part, they are easily winning fixtures that they previously might have struggled with. -- Jonathan Johnson
Who's next? Dijon, Marseille, Nice
JUVENTUS: (WWWWWWD) - Paulo Dybala coming of age
Despite only dropping two points this season, Juve have yet to recover their balance and overall strength from last season. With the defence looking vulnerable and Gonzalo Higuain suffering from malaise in the early stages, Juventus have had to rely on Paulo Dybala and his incredible talent to ensure success and an impressive start to the season.
Blessed with mercurial talent and remarkable efficiency, the young Argentine has scored 10 league goals this term, just one goal fewer than his total tally last season. Delighting onlookers with his creativity and perfect finishing, Dybala's genius play has inspired the team to keep winning, while his penchant for a hat trick and the constant threat he provides going forward is papering over the cracks that have yet to be resolved on a tactical level. -- Mina Rzouki
Who's next? Lazio, Udinese, SPAL
INTER MILAN: (WWWWDWW) The Luciano Spalletti effect
Inter have been successful in spite of -- or rather, partly as a consequence of -- their new style. In trying to impose a more pass-oriented approach, Luciano Spalletti has asked his defence to play very deep, which may explain why Inter have conceded a league-low three goals so far. Meanwhile, new signing Milan Skriniar has hit the ground running, and looks to be a star in the making.
They may have had some lucky breaks on the way such as a favourable fixture list and Roma hitting the post three times but the promising thing about Inter is that they've barely got started. It's not a question of if the likes of Mauro Icardi, Ivan Perisic, Roberto Gagliardini, Borja Valero and Matias Vecino will light up the league, but when. Spalletti's pragmatism needs to be emphasised, too: in trying to build from the back, he's made it clear that the Nerazzurri need to be balanced to make progress in this Serie A. -- Edoardo Dalmonte
Who's next? AC Milan, Napoli, Sampdoria