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The Champions League is back on Paramount+. Five games stand between the field and glory. Here is a factor that could swing each of the quarterfinals.

Bayern Munich pay the penalty for sloppy errors

Since the start of March, Bayern Munich have conceded five penalties. Is that something or nothing? Spot kicks can often tell a misleading story. Even five of them in such a short period of time is an exceedingly small sample size. A few contentious calls from a referee going one way or another can paint an extremely false picture of a team's qualities, as teams such as Ole Gunnar Solskjaer's Manchester United have proven in recent years.

There may, however, be something to at least a few of Bayern's slip ups inside their penalty area, which are numerous enough that not all of them have ended in spot kicks, to suggest that an attack as relentless as Manchester City's can bait some errors out of them. After all, in the last four seasons of Premier League football, Pep Guardiola's side have won 36 spot kicks, four more than any other team. They are very good at baiting challenges and drawing despairing tackles and right now Bayern look like a side who could be forced into those sorts of actions.

Take the ease with which Freiburg got in behind in their 1-0 defeat at the weekend. Michael Gregoritsch really is not in a dangerous position below, even when he spins Matthijs De Ligt to create space for a cross down to the byline. There is no one to really aim at until Alphonso Davies just switches off.

Gregoritsch earns a crossing position and Doan beats Davies to the ball Wyscout/Bundesliga

Ritsu Doan ghosts in behind Davies and Bayern are extremely lucky that his shot clattered back off Yann Sommer's post rather than nestling in the net. If there were any game where Bayern might have been a little more focused it was Saturday's, four days after a defeat to the same opposition where new manager Thomas Tuchel had chastised his players for their lack of bite in defending their penalty area. "You have to put your body in there, be more stable, be tougher," he said of the string of missed clearances and lost duels that resulted in a, you guessed it, 95th minute penalty for Freiburg. At Chelsea, Tuchel sparked his side into Champions League winning mode by almost immediately fixing an error prone defense, one which vastly outperformed its own impressive skill level almost immediately. It would appear he has not caught lightning in a bottle again.

Of course, these sorts of mistakes happen, but before and after Julian Nagelsmann's sacking they have happened a lot to Bayern.  Perhaps this sloppiness is a reflection of a defense that has chopped and changed so frequently in recent months that it has lost its collective instincts. Maybe the organizational skills and sweeping qualities of Manuel Neuer are being missed. Or perhaps a side that is so used to dominating territory with full backs so far advanced that they are functionally operating as forwards is necessarily going to be vulnerable in the sort of spots that Doan nearly exploited on Saturday.

Whatever the reason, these are the sort of clumsy moments that can result in penalties or goals out of nowhere. Make them against City and there will not be an opportunity to make amends.

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Onana give Inter foothold in the tie

There might have been no better goalkeeper in the Champions League this season than Andre Onana, the man who arguably contributed more than anyone else to Inter Milan scraping past Porto in the round of 16. It might seem a little curious to highlight him at this moment, a few days after he was bamboozled by an Antonio Candreva cross in a 1-1 draw with Salernitana, but even as the clean sheets have dried up in Serie A, Onana is proving himself to be an exceptional goalkeeper.

Indeed according to Opta's advanced goalkeeping statistics, there is daylight between the Cameroonian and the rest of the field in the Champions League. He has conceded 7.7 goals fewer than the post-shot expected goals (xG) tally says he should. The next best performing goalkeeper on that list is Club Brugge's Simon Mignolet at 4.1. These metrics can be notoriously loud -- few would argue that the top two on these particular rankings are the best shot stoppers in Europe -- and by the quarter final stage of the Champions League we remain firmly in the realms of low sample size, but when someone is performing as well as Onana, conceding almost a goal fewer per 90 minutes than shot data says he should, it is worth taking note.

Shots faced by Andre Onana in the Champions League this season. Balls coloured blue are saves, white are conceded Twenty3

There might be some air in the numbers, but Onana has been an impressive all-round goalkeeper for some time now, a player that Europe's top sides were clambering to secure on a free before a drug ban that threatened to spoil his career. Inter's faith has been rewarded. They have secured a thoroughly modern goalkeeper who is extremely strong with his feet and, as the graphic below shows, has the springiness in his legs to get down quickly and make big saves.

Of course it might all come crumbling down for Onana in this junior varsity Champions League quarterfinal. Benfica will put pressure on his goal, they average around 14 shots per game in European competition this season and have scored 22 goals, though that comes off an xG hot streak that is perhaps just as likely to cool down as Inter Milan's goalkeeper. There is an awful lot that is unknowable about Benfica, still untested against the very best in the Champions League (their group stage opponents Juventus and Paris Saint-Germain have spent much of this season finding new ways to underwhelm). What is clear, though, is that Onana is the sort of top goalkeeper who can keep a fairly lacklustre side in the game.

Chelsea hold their own in midfield battle

On paper this ought to be a walkover masquerading as a competitive football match. The reigning champions of Europe taking on a thoroughly midtable English side, one now led by a manager who was well on course to shepherd Everton into the Championship? This could be in the bag for Real Madrid by half time in the first leg.

And yet there is half a cause to hope that Chelsea might at least not be ripped to ribbons in the same way that Liverpool were in the last round. On that occasion, Luka Modric and company got ahold of midfield after a shaky start to the first leg, passing and gliding through an Anfield engine room where the fires have long since gone out. From that platform it was all too easy for Madrid to throttle the life out of the tie; Liverpool had no ball progression or ball-winning qualities to speak of.

That ought not to be the case against Chelsea, particularly with Frank Lampard having shrewdly concluded that there was no value in gambling with N'Golo Kante's fitness even if it meant defeat to Wolverhampton Wanderers. Madrid will need no reminding of the merry dance the Frenchman led them on in 2021, as exceptional a performance as this column has ever seen from an individual player in the Champions League. Injuries and age mean Kante might not repeat that. No matter, Chelsea have other weapons that can tilt the midfield battle in their direction.

Enzo Fernandez has swiftly adapted to life in the Premier League after his British record £107 million move from Benfica. Since his arrival in the Premier League, the Argentine has completed 101 passes into the final third, nine more than any other player. Per 90 minutes he averages more than anyone except Thomas Partey, and is notably just ahead of Jorginho, the player he succeeded as Chelsea's tempo setter and No.5. Statsbomb 360 data ranks him second to only Trent Alexander-Arnold in terms of line breaking passes.

The direction in which Fernandez passes the ball in Premier League matches this season Twenty3

As the graphic above indicates, from every position on the pitch he is pushing Chelsea forward with his passing. Fernandez has completed 744 passes since arriving in the Premier League and just 81 have gone backwards. He is completing a higher proportion of forward passes than counterparts such as Rodri, Partey and Fabinho.

What will all this mean against the defending champions? It may not be enough to win Chelsea the tie, after all the Blues look lackluster in front of goal and will be facing a side that always finds a way to get the ball across the line. However, Madrid's mighty midfield is at its least effective when it is having to cover ground. If Kante and Fernandez can make their mark on this tie, things may not be as easy for Luka Modric and Toni Kroos as many expect.

Napoli get the win... but wobble at set pieces

Rarely can a meeting between two imminent Champions League opponents have felt quite as irrelevant as Napoli's 4-0 loss to AC Milan on April 2. This was not the first of a great series of totemic clashes akin to Real Madrid and Barcelona in 2011. It was scarcely even an amuse-bouche for what was to come on the European stage. Milan knew when they arrived at the Stadio Diego Armando Maradona that they were in for an almighty scrap to secure a top four berth next season. Napoli must know, even if they will not admit it, that the Scudetto is in the bag. Even Luciano Spalletti acknowledged the motivation gap between his side and Milan.

"We know that Milan came into the match with the fear of losing it," the Napoli coach acknowledged. "We probably came into the match with the belief that it could be a filler match towards the Champions League. That made a difference to the motivation for the match." There will be no motivation gap this time out and even if Napoli will be a weakened opponent without Victor Osimhen, who trained on his own on Monday, they will not be anything like the side who so meekly surrendered after their early setbacks last time they faced Milan. If nothing else it's hard to believe that Khvicha Kvaratskhelia might go a third game without a goal and assist.

Such have been the strides Napoli have made from a top three or four Italian side to a top three or four side worldwide it can seem churlish to pick flaws. No one wants to rain on this magnificent parade and yet no team is bulletproof. Samuel Umtiti and his Lecce team mates proved as much on Friday, giving the Napoli backline all sorts of difficulties from set pieces before succumbing to a 2-1 loss. 

They are not the first. Napoli's defense has given up the second lowest xG to opponents of any team in Serie A this season, just 26.7. However nearly a quarter of that has come from set pieces, where they rank eighth in terms of xG allowed. Milan have not been a team who have made most of their opportunities off dead balls but in Olivier Giroud they have at least one player who can pose all sorts of difficulties for the Napoli backline.

A lot would have to go right for this relative weakness in the Neapolitan backline to be exposed and even if it does, the sheer weight of the talent at the other end of the pitch should be enough to ensure that the south emerges victorious in this Italian grudge match. But there is a hint of a vulnerability there for Milan to exploit.