In the fourth round of matches in the Champions League group stage, title holder Bayern Munich, Manchester City, Atletico Madrid and Barcelona became the first teams to qualify for the knockout phase. Here are five thoughts to chew on from this week's matches:
ARSENAL FOR REAL: Perhaps this year, Arsene Wenger really has the makings of his first trophy-winning team since the side that won the FA Cup in 2005.
In becoming the first English side to beat Borussia Dortmund at its stadium in the Champions League on Wednesday night, Arsenal showed Europe it's a serious opponent and not simply flattering to deceive as in previous years with pretty but too often ineffective soccer.
From the outset this season, this week always looked like the first acid test of Arsenal's ambitions, with three formidable opponents - Liverpool, 2013 Champions League runner-up Dortmund and Manchester United - in three successive games.
Two down, one to go.
The Premier League leaders beat Liverpool 2-0 at the Emirates Stadium last Saturday.
Arsenal showed resilience, poise and patience in keeping Dortmund scoreless and in waiting 62 minutes for its first targeted attempt on goal, which Aaron Ramsey headed in.
In his first encounter with Wenger, new Manchester United manager David Moyes is sure to regard the Gunners with added respect on Sunday.
CRISIS? WHAT CRISIS? After successive seasons when he seemed to float on air, Lionel Messi's failure to score in four consecutive La Liga games - for the first time since 2010-11 - felt unnatural, like a solar eclipse.
Well, fear not, the ''drought'' is over before it really began.
The four-time world player of the year looked almost back to his former brilliant self, coolly slotting home a penalty and then darting through the AC Milan defense for his second goal in a 3-1 victory on Wednesday that secured Barcelona's spot in the next phase of the competition.
Normal business is resumed.
GOALKEEPERS STILL HAVE IT: Have no doubt: Iker Casillas is still a world-class goalkeeper. At 32, an age when questions about his reflexes and ability to compete at the top will only increase, Casillas has been spending too much time of late warming Real Madrid's bench. The club's formerly undisputed No.1 choice in goal has even talked of possibly needing to leave in January's transfer window.
Given a rare start on Tuesday by coach Carlo Ancelotti in Group B against Juventus, Casillas seized the chance to remind Europe of his quality. Without his saves, Madrid could easily have lost this game - its defense was unconvincing - instead of leaving Turin with a 2-2 draw and one foot in the last 16.
At the other end, Gianluigi Buffon also looked reassuring in Juventus' goal. Buffon and Casillas swapped shirts and hugged after the match where they both made a case for going to the 2014 World Cup. It would be their fourth for each (Buffon's fifth if you also count 1998, when he was an unused substitute). Together, they've played 288 times for their countries. Amazing.
At Manchester City, for its 5-2 dismantling of CSKA Moscow, coach Manuel Pellegrini again put Costel Pantilimon in goal instead of the recently error-prone Joe Hart.
That's not good for England to have its 'keeper looking fidgety and forlorn on the City bench eight months out from the World Cup.
SCORES WHEN HE WANTS: With Sergio Aguero, the fans' chants for once feel justified: Manchester City's striker is so sublimely talented that he really does seem to score when he wants.
Aguero's pair against CSKA Moscow - the second slotted into the bottom corner after a marvelous spin past Aleksei Berezutski - means he has now found the net in each of his last six games, scoring a total of nine goals.
Big ''ifs,'' of course, but with such skills, Aguero could challenge for the Ballon d'Or next year if he secures City some trophies this season and outshines Argentina teammate Messi at the 2014 World Cup.
AWKWARD: Although Champions League soccer is often high quality, arguably better than at the World Cup, the same cannot always be said of the news conferences that players, coaches and the media endure before games.
Perhaps because they're addressing reporters they are less familiar with or because it's hard to wax lyrical about a match they've yet to play, managers and players often seem to become particularly wooden under the Champions League media spotlight.
Consider these banalities from Wenger before his team's 1-0 defeat of Dortmund:
''Dortmund is a good side.''
''It's difficult to predict what will happen, that's what makes football great.''
''At least you have a guarantee that the two teams will try to win the game.''
You don't say, Arsene.
John Leicester is an international sports columnist for The Associated Press. Write to him at jleicester(at)ap.org or follow him at https://twitter.com/johnleicester