Two big players returned to their former clubs and had very different "debuts" in Cristiano Ronaldo at Manchester United and Antoine Griezmann at Atletico Madrid, while Bayern Munich showed how they're still the clear front-runner to win the Bundesliga this season and make it a stunning 10 in a row.

Here's the big stuff you need to know from the soccer weekend around Europe.

Jump to: Talking points | Best goals | Teams in trouble | MVP of the Weekend

Four talking points

Not an easy "second debut" for Griezmann

The 58 minutes Antoine Griezmann spent on the pitch during Atletico Madrid's dramatic 2-1 win at Espanyol on Sunday were all it took to demonstrate that his reintegration after two years in Barcelona is very much still a work in progress. Diego Simeone was forced to innovate so he could squeeze Griezmann into his starting XI, fielding an unusually attacking line-up with the new arrival playing off Luis Suarez and alongside Angel Correa, Marcos Llorente and Yannick Carrasco in a strong attack.

Numerous tactical tweaks followed as the coach tried to make it work, including a triple half-time swap and formation change (the 5-4-1 became a 4-3-3) before eventually hauling Griezmann off after an hour with Atletico still 1-0 down. He had touched the ball 33 times, completed 17 passes and taken two shots, both off target. France teammate Thomas Lemar, who went on to score a dramatic late winner in the 10th minute of injury time, was far more influential in a similar amount of time on the pitch.

It's much too early to start drawing conclusions, and there's every chance Griezmann will eventually come good. But with a bigger, better squad than ever before, Simeone will have to start making some tough decisions about who plays and who doesn't. Expect fireworks if Griezmann and Suarez end up battling it out for one spot in the team. -- Alex Kirkland

Man City win quietly on big Saturday

It seems improbable that a team full of superstars managed by one of the greatest coaches of all time can go under the radar but Manchester City seem to do it again and again. Last season, while everyone was talking about the possibility of Manchester United and Liverpool going head-to-head for the Premier League title, City quietly strung a run of wins together and won in a canter.

There weren't many eyes on their trip to Leicester on Saturday, either. and hidden away on a Saturday at 3 p.m. and with the circus at Old Trafford to watch Cristiano Ronaldo, Pep Guardiola's team won 1-0. Leicester (under manager Brendan Rodgers) are now one of the Premier League's established top teams, and to win there immediately after the disruption of the international break is no easy feat.

Man United and Chelsea are top of the table after four games, but City are just a point behind in third having scored 11 times already this season and conceding just once. They didn't get Harry Kane or Ronaldo in the summer transfer window, but with Jack Grealish added to an already stacked squad. they are stronger than they were last year. It is easy to forget, but they're still the team to beat. -- Rob Dawson

Bayern Munich's form is ominous for the Bundesliga

There was a school of thought that it could take Julian Nagelsmann a little while to settle into life at Bayern Munich. He'd gone from the chasing pack, as manager of RB Leipzig, to the chased. But on his return to the Red Bull Arena, there was no room for sentimentality as his Bayern Munich side swept aside one of their challengers with a 4-1 victory. In truth, they could've had a few more goals, but Nagelsmann was so confident the job was done that he took off Robert Lewandowski after 58 minutes with a Champions League game against Barcelona up next in midweek.

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The fastest debut goal in @premierleague history. #CPFC | https://t.co/utMcYSlISB pic.twitter.com/RhUm4NpaYA

— Crystal Palace F.C. (@CPFC) September 11, 2021

We hoped Saturday's Bundesliga blockbuster would be tighter and that Leipzig could land an early blow on Bayern's hopes of winning a 10th straight Bundesliga. But instead this was a flex from Bayern at their dominant best, with Lewandowski scoring a penalty, Jamal Musiala coming off the bench to score a great goal just before half-time and Serge Gnabry and Eric Choupo-Moting also getting in on the act. Joshua Kimmich was outstanding for Bayern, Leroy Sane is playing himself back into form, and their versatility (they finished with Niklas Sule at right-back and Josip Stanisic in midfield) suggests Nagelsmann's position-fluid philosophy is starting to take shape.

Meanwhile, the result is a body blow for Jesse Marsch. He replaced Nagelsmann at Leipzig and has endured a rocky start; despite off-season departures and unexpected absences due to COVID-19, they have just one win from their first four matches. The first challenge will be to work out their attacking fluidity, as they were repeatedly caught offside by Bayern's high press, but they have the brains in Emil Forsberg, Dominik Szoboszlai and Dani Olmo to sort that out. -- Tom Hamilton

It's going to be tough to stop Chelsea

And then there's Chelsea, who are genuine contenders under Thomas Tuchel and have built a squad capable of lasting the distance.

Chelsea had made seven changes from their previous trip to Liverpool before the international break, but still managed to clock up an impressive 3-0 victory over the ever-improving Aston Villa. Villa were brilliant in spells and had enough about them to get a result at Stamford Bridge, but Chelsea are showing early title-challenging form.

This was a tale of two new signings. First, you had Romelu Lukaku who has returned to the Premier League with ease. He has three goals in two matches, thanks to his brace against Villa on Saturday. The first came after as he darted on to a lovely through-ball from Mateo Kovacic to slot home, while the second was a late, perfectly judged effort from outside the box.

While Lukaku played as if he'd never been away, Saul struggled on his Chelsea debut. The midfielder, arriving on loan from Atletico Madrid with minutes left on Deadline Day, was guilty of surrendering the ball three times in dangerous positions in the first half, with Edouard Mendy and Thiago Silva keeping Villa at bay. Saul was substituted at half-time and needs time in order to be a success, but Tuchel has the options at his disposal to keep his first XI fit.

Ross Barkley and Ruben Loftus-Cheek were both on the bench, as a reminder of their huge squad, and Chelsea's incredible strength in depth suggests they will be in the mix come May. -- Hamilton

Three must-see goals

Bruno's goal the one to remember

Cristiano Ronaldo made it his day against Newcastle, but Bruno Fernandes' goal to make it 3-1 is worth a watch. The finish was sublime to beat Freddie Woodman from outside the box, but David De Gea also deserves a mention. After all, it was his pin-point kick out of his hands to Mason Greenwood that started the move and meant Newcastle's defence were all over the place by the time Fernandes found the ball at his feet. -- Dawson

Carrasco crushes one for Atletico Madrid

Thomas Lemar's 99th-minute winner for Atletico Madrid at Espanyol will get the headlines, but it was Yannick Carrasco's strike 20 minutes earlier that was the goal of the game. Atletico were 1-0 down and in trouble when Carrasco -- who started the match at wing-back before being pushed further forward in search of an equaliser -- received the ball from Renan Lodi on the edge of the six-yard box. It looked like he'd been crowded out by Espanyol's defenders before showing a mixture of tenacity to win the ball back, balance to turn towards goal and poise to pick his moment to fire low past goalkeeper Diego Lopez.

Carrasco's contribution since his return to Atletico last year has been drastically underrated. -- Kirkland

"DON'T FORGET ABOUT ME."

Bruno Fernandes scores for @ManUtd. ? #MUFC pic.twitter.com/zTu8tUlmOa

— NBC Sports Soccer (@NBCSportsSoccer) September 11, 2021

Edouard's dream debut

When a team spends £14 million on a striker, you expect returns. Odsanne Edouard's record in Scotland was superb, with 86 goals across five years with Celtic, but the Premier League is a different proposition. Except it took Edouard just 29 seconds to score for his new side Crystal Palace, making it the quickest goal by a debutant in the history of the Premier League.

The Eagles were already 1-0 to the good against 10-man Tottenham when Edouard was introduced in the 83rd minute. His first involvement was to challenge for a header and when Wilfried Zaha picked up the loose ball, Zaha charged down the left flank and found Edouard inside the box. The striker took one touch with his left and then placed it through Ben Davies' legs, sneaking the ball inside Hugo Lloris' left post. And he backed it up with another goal in injury time as he linked up with Michael Olise and Conor Gallagher.

"I'm very happy, it's a dream come true," Edouard said afterwards. "I worked very hard for this moment." -- TH

Huge goal by Yannick Carrasco to tie it for Atleti! pic.twitter.com/jMJJbC22GM

— ESPN FC (@ESPNFC) September 12, 2021

Two teams that should be worried

Celta Vigo

Hopes were high for Celta Vigo this season under Eduardo Coudet. The Argentinian coach took the Galicians from bottom of the LaLiga table to the brink of European qualification last year, playing an exciting, high tempo style that saw Coudet branded an attacking version of Diego Simeone. They've had a tough time of it so far this campaign, though, and went into Sunday night's game with Real Madrid with a draw and two losses to show for their opening three games.

Things were looking up when they went ahead 1-0 through Santi Mina -- and again when they led 2-1 thanks to Franco Cervi -- as Celta threatened to spoil Madrid's party on their return to the Bernabeu stadium after 560 days away during the coronavirus pandemic. The subsequent Celta collapse to lose 5-2 was dispiriting and highlighted the fact that this team are as defensively fragile as they are vibrant in attack. Coudet had better sort things out fast. -- Kirkland

Juventus

Three games into the fresh Serie A season and Juventus are still without a win. After a summer of change in which Massimiliano Allegri came back to his old home, and Ronaldo and Andrea Pirlo left, it's become abundantly clear it will take time for the Allegri magic to return.

Juve won five titles under their old boss, but have made a torrid start to the 2021-22 campaign. After a 2-2 draw at Udinese and a defeat at home to Empoli, they hoped to get their season back on track at Napoli. Paulo Dybala, Juan Cuadrado, Alex Sandro, Danilo and Rodrigo Bentancur were all absent and though they started well through Alvaro Morata's 10th-minute goal, they surrendered the points through Matteo Politano's second-half strike and Kalidou Koulibaly's late winner. Juve looked to be in control of the match, but their leaky defence again let them down.

Allegri said they took "giant steps forward" against Napoli, but their next match against AC Milan will be a must-win. A crumb of comfort for Juve fans is they had this many points after their first three matches in the 2015-16 campaign, and ended up winning the Scudetto anyway. -- Hamilton

MVP of the weekend: Cristiano Ronaldo

It can only be him. The eyes of the world were on the beginning of his second spell at Manchester United, and the 36-year-old still delivered. He admitted afterwards he was "nervous" ahead of his Old Trafford comeback, but it was hard to tell. With very little training or match fitness under his belt, the Portuguese superstar scored twice against Newcastle. The first was a tap-in after Woodman had spilled Greenwood's speculative shot; the second came thanks to a burst of pace, a delicate touch and a snap-shot through the Newcastle goalkeeper. He's a very different player to the one who left United for Real Madrid in 2009, but still, clearly, a very good one.

After deciding to leave Juventus this summer, it would have been easy for Ronaldo to pick a league not quite as challenging as England's top flight. He has nothing to prove here after six trophy-laden years at Old Trafford, but the hunger to achieve more and more is still there. There should not be any doubts about Ronaldo after what he has done over the course of an incredible career as any remaining questions were answered against Newcastle. -- Dawson