Napoli vs. Barcelona (Agg. 1-1)

In their first encounter on February 26 this year, Napoli's Dries Mertens opened the scoring with an incredible goal that would have sent the Stadio San Paolo into a frenzy were any fans allowed to attend. Barcelona's Antoine Griezmann pulled one back early into the second half but it was still mostly the home side's game; proof of which was Arturo Vidal being sent off in the 89th minute for back-to-back yellow cards after losing his temper with left-back Mario Rui.

Mertens couldn't finish the game and left the pitch with an injury. Were this a standard Champions League season, he would have been unavailable for the second leg. Instead, he's had months to recover and is liable to follow up on his first leg scoring. However, Barcelona's savior Griezmann is unlikely to play due to a thigh injury he sustained in July in a game against Real Valladolid.

His absence isn't going to change much. Under manager Gennaro Gattuso, Napoli have been hungry for success and in the group stage, they were the only team out of themselves, Liverpool, Red Bull Salzburg and Genk to not suffer a loss. They are grinders and they see a big opportunity ahead of them in this Barcelona side which is considered weak, with or without Griezmann.

Something is rotten in the state of Catalonia. On paper, it's difficult to criticize FC Barcelona this year. They finished second in La Liga behind Real Madrid by a gap of only five points (and they were 12 points ahead of third-placed Atletico Madrid) and got to the quarterfinals of the Copa Del Rey.

However, La Liga is a two-horse race and they have been outclassed by their only real rivals, Real Madrid, in both the league and cup. And that's not only in head-to-head results: Barca are a wealthy team made up of superstar players and yet they've been struggling against teams they should have been turning over with ease. Manager Quique Setien's tenure with the club will likely be decided by this fixture.

The desire to get at least one step ahead of Real in the Champions League may be enough to secure a win tonight, but they will need to be firing on all cylinders to do it.

Bayern Munich vs. Chelsea (Agg. 3-0)

The first leg game at Stamford Bridge was a true mauling. The first half was one of the most dominant 0-0 performances of all time, with Bayern consistently being dangerous and running rings around the backline of Cesar Azpilicueta, Andreas Christensen and Antonio Rudiger, only to find their persistent attack repeatedly thwarted by a brave performance from Willy Caballero.

And then during the half time break, manager Hansi Flick must have come up with a new gameplan, because they then put three past Caballero – two of which came almost immediately as Serge Gnabry got a brace in the 51st and 54th minute. Champions League top scorer Robert Lewandowski finished the job with a goal of his own in the 76th minute.

Since then, Bayern have been business as usual and won both the Bundesliga title and the German Cup (DFB Pokal) while Chelsea are definitely improving but still chaotic. They reached the FA Cup final and lost to Arsenal, have wins over Premier League big boys like Manchester City and Leicester and somehow have losses to Premier League small fries like West Ham and Sheffield United.

As Bayern's last competitive game – if it could be called that, as they had already won the league – was on June 27, it's possible they will be rustier than Chelsea who were competing as recently as last Sunday. However, the longer season has led to more injuries and nine first team players are either confirmed out or doubtful to play in tonight's game: Willian, Christian Pulisic, Azpilicueta and N'Golo Kante are all on that list.

A Chelsea comeback at the Allianz Arena feels impossible at this point, though it should be recalled that the last time the two sides faced each other here, it was "written in the stars."