The UEFA Champions League is the competition that sorts the contenders from the pretenders. League play is fine, but continental clashes allow us to gauge the strength of Europe's best.
As you've probably guessed, last week's action plays a formative role in this week's European Club Rankings, a list of the continent's top teams in order of estimated strength and form at this stage of the season. Prepare for some big changes, as the top five has been shaken up notably.
20. Roma (-4)
Roma are all over the place. With pressure ramping up on Eusebio Di Francesco after back-to-back defeats, Wednesday's home clash with Frosinone is starting to look like last chance saloon for the manager.
19. FC Porto (New!)
We're really short on high-performing teams right now. FC Porto nab 19th almost by default, replacing Benfica after drawing their Champions League opener with Schalke 1-1, while their rivals lost 2-0 at home to Bayern Munich.
18. Marseille (-3)
It's been a week to forget for Marseille, who lost their Europa League opener to Eintracht Frankfurt 2-1 on Thursday, then were beaten soundly by Ligue 1 rivals Lyon 4-2 on Sunday.
17. Inter Milan (+2)
Slowly, Inter are starting to come good. They've won three of their last four games and beat Tottenham in their Champions League opener 2-1, lifting the doom and gloom around San Siro.
16. Arsenal (+1)
It's four wins in a row for Arsenal, but whether it's that streak or the fact they kept their first clean sheet of the season that pleases Unai Emery more is a tough call. If it's the latter, he owes Petr Cech a big thank you.
15. Lyon (+3)
Lyon shocked Europe with their 2-1 Champions League win over Manchester City last week, and they carried that momentum into the weekend, beating Marseille to make it a wonderful five days. This is what Lyon are capable of; why don't we get to see it more often?
14. Lazio (Stay)
Lazio keep chalking up wins; that's four in succession now. They're used to coping with the Serie A-Europa League grind as they did it last term, and they've started 2018-19's edition of it well.
13. Tottenham Hotspur (-1)
Spurs' 2-1 win over Brighton on Saturday ended a three-match losing streak. Granted, those three defeats came against strong sides, but top teams don't put together those kinds of runs. Winning at the Amex Stadium can't stop them from dropping.
12. Manchester United (+1)
United made light work of Young Boys last week, securing a 3-0 win away in the Champions League to set their European ball rolling. They looked flatter at the weekend—admittedly against a much better opponent in Wolves—but managed a 1-1 draw to keep them ticking over.
11. Borussia Dortmund (Stay)
Twice in the space of a week, Christian Pulisic saved Borussia Dortmund's bacon late on. An 85th-minute winner against Club Brugge was followed by an 84th-minute equaliser against Hoffenheim. It keeps them in 11th.
10. Napoli (Stay)
Amid Inter Milan's slow start, Roma's mini-crisis and Lazio's difficult schedule, Napoli's solid beginning to the campaign has gone a little unnoticed.
Lorenzo Insigne's been at the heart of it, netting four goals in five Serie A games as he takes on a leading role in this team. It's crucial that the point of emphasis of this team changes, as with Maurizio Sarri and Jorginho gone, they have to be different; they have to remodel themselves.
9. Atletico Madrid (Stay)
Perhaps things are starting to turn for Atletico Madrid.
Last week they won two games, both away from home, both against tough opponents. It's all in stark contrast to the preceding weeks, where they won just one of four games and cast heavy doubts over their own title credentials.
They went behind midweek against Monaco and had to claw their way back, but did so and took control of their Champions League group in the process with the 2-1 win. This weekend saw them resume normal service in beating Getafe—a side that have never even scored against them while Diego Simeone has been in charge.
8. Chelsea (Stay)
This weekend saw Chelsea's winning start to the season come to a halt, as West Ham held them to a 0-0 draw at the London Stadium Sunday.
It's a result that has been coming, as the Blues system is reliant on the front three doing almost all of the work up top. With no help from the midfield, an off day from Eden Hazard and Co. can result in going scoreless.
They had their chances, and opposing goalkeeper Lukasz Fabianski was excellent, but they were unable to make it six wins in a row in the Premier League.
7. Paris Saint-Germain (-1)
Paris Saint-Germain are still perfect in Ligue 1 after winning their sixth straight game this weekend against Rennes 3-1, but that's not the battleground anyone's judging them on.
The Champions League is where we measure their strength, and they're off to a disappointing start following that 3-2 loss to Liverpool at Anfield.
Sure, it was only by a goal and they only conceded the winner at the death, but the performance was poor—particularly from Edinson Cavani, Neymar and the midfield three—and they never felt capable of sticking with the Reds.
6. Manchester City (-4)
Manchester City beat Cardiff City 5-0 on Saturday in a blitz of attacking power without David Silva, Kevin De Bruyne, Benjamin Mendy and several others, but no one's really talking about that.
They're still talking about how they collapsed inward against Lyon last week in the Champions League, falling two behind, losing the midfield battle and failing to recover. For whatever reason, Man City plus European competition isn't a mix that's working well right now; they've lost their last four straight in the Champions League.
It's a defeat that costs them in the Club Ranking, as they fall out of the top three and are no longer the top-ranked English side.
5. Real Madrid (Stay)
Last week, Gareth Bale confirmed what we were all thinking: The post-Cristiano Ronaldo Real Madrid has a more holistic, unified feel to things. "I suppose there is more of a team, more working as one unit rather than one player," he told the Daily Mail.
We saw evidence of this against Roma midweek, where they made one of Serie A's strongest sides look absolutely terrible. The Italians couldn't live with a team-wide pressing and intensity from Madrid that led to a 3-0 victory.
They followed that up with a 1-0 win over Espanyol, with Marco Asensio opening his account for the season to haul in three points.
4. Bayern Munich (Stay)
It's tough to escape the feeling that Bayern Munich are in a league of their own right now. Every season we look for the nearest challengers to their Bundesliga crown, but this time around there might not be one worth selecting.
A 2-0 victory away to Schalke—the side that finished second last season and qualified as those "nearest challengers"—didn't look particularly tough to achieve this past weekend. Benfica didn't put up much of a fight midweek either.
3. Juventus (Stay)
Despite the circus of Cristiano Ronaldo's red card on his Juventus Champions League debut, a 10-man Bianconeri outfit prevailed 2-0 in a game against Valencia that finished with an incredible three penalties awarded.
The immediate concern following that match was that the Portuguese's ban would be extended due to the age it took him to leave the pitch, but the Mirror's Richard Tanner reported he'll miss just one game, leaving him free to face former club Manchester United at Old Trafford on Matchday 3. Narrative rescued.
At the weekend normal Serie A service was resumed, where Juve beat Frosinone 2-0 to maintain their perfect start to the campaign.
2. Barcelona (-1)
There was a lot to like about the scoreline Barcelona racked up against PSV Eindhoven—4-0—but some of the defending on show was horrid. Samuel Umtiti's late, needless red card summed things up for them in a way, but it's tough to be too critical when a team wins so well.
That mindless defending filtered into their weekend match against Girona where Clement Lenglet was sent off, Gerard Pique slipped and gifted a goal and the most the team could muster was a 2-2 draw.
It's a combination of performances that sees them drop from top spot.
1. Liverpool (+6)
"This is Anfield...this is what they do," Thomas Tuchel said of Liverpool's excellent midweek performance against Paris Saint-Germain in the Champions League, per the MailOnline.
He's been on wrong end of the stadium's effect there before, too, as his Borussia Dortmund team lost 4-3 to the Reds in the Europa League in 2016/7.
Liverpool followed that win up with a comfortable victory over Southampton on Saturday, making it seven straight victories to begin the season; that's the sort of form you can't ignore—particularly with wins over PSG and Tottenham mixed into that—and they're rewarded with a big boost that takes them to No. 1.
Helping them along the way were slips by Barcelona and Manchester City; had neither fallen short, perhaps the Reds would have placed third or second, rather than first.