In the Champions League's round of 16, Bayern Munich will meet Paris Saint-Germain in a titanic meeting of the two teams that took part in the final in 2020.

PHOTO | COURTESY Bayern Munich players train ahead of their UCL clash against PSG on Tuesday 14th

Ahead of Tuesday's first leg, AFP Sport examines some of the crucial matchups that could influence where the match is won or lost:

Julian Nagelsmann vs. Christophe Galtier

PSG's domestic play has deteriorated significantly since the turn of the year after a good start, and coach Galtier is now facing a crucial calendar period without Kylian Mbappe.

PHOTO | COURTESY  Bayern Munich manager Julien Nagelsmann in one of the UCL matches

The French player, who has seven goals this season in the Champions League, will miss the first leg due to a thigh injury.

At the same time, Lionel Messi is also doubtful after suffering a hamstring injury during Wednesday's 2-1 French Cup loss to Marseille.

Galtier must devise a strategy that will allow a depleted PSG—whose team was also struck by a stomach ailment over the weekend—to escape another European failure because Neymar has yet to regain his best form since the World Cup.

PHOTO | COURTESY Christophe Galtier PSG Manager

Following three consecutive draws last month, Bayern went through what head coach Nagelsmann called a "results crisis," but it now seems they have turned the corner.

Critical player injuries have also hampered the 35-year-old Nagelsmann, although expectations in Bavaria are as high as ever thanks to cover the club brought in in January.

Yann Sommer vs. Gianluigi Donnarumma

The Italian goalie, who made a costly error when Real Madrid eliminated PSG in the round of 16, is now firmly established as their starting goalkeeper.

Before the arrival of Donnarumma, whose signing is to help the French champions win Europe's top club prize, PSG twice reached at least the semifinals with Keylor Navas in goal.

Bayern has replaced Manuel Neuer, who has a leg injury and will be out for the remainder of the season. Injury while skiing in December with Yann Sommer of Switzerland.

While Sommer, 34, has previous Champions League experience with Borussia Moenchengladbach and Basel, the scrutiny with the six-time European champions will be far more intense.

Verratti versus the German trio

Joshua Kimmich and Leon Goretzka, both Germany internationals, will likely patrol the middle of the field for Bayern, while the excellent Jamal Musiala will probably play a more forward position.

With 14 goals, Musiala, who is still under 20, leads Bayern in scoring, and Goretzka and Kimmich are two of the complete midfielders in the world.

However, PSG has historically struggled in this area since they rely so much on Marco Verratti, whose health is currently under review as he receives therapy for a bad hip.

Vitinha's form has fallen, Fabian Ruiz and Carlos Soler have struggled to adjust after joining in the summer, and Renato Sanches is probably out of both legs with a hamstring injury.

Sergio Ramos vs Eric-Maxim Choupo Moting 

In the final three years prior, Choupo Moting made his last appearance for PSG during a lacklustre stay in the French city, and he ended up on the losing side.

The Cameroonian striker's move to Bayern first appeared implausible. Still, his support Chuopo Moting Cannot emphasize this season for a club adjusting to the absence of Robert Lewandoski and Sadio Mane, who is out due to an injury, and Lewandoski currently plays for La Liga side Barcelona in Spain.

PHOTO | COURTESY PSG players train ahead of their UCL tie against Bayern Munich

Only Musiala has more goals than he does, and by keeping defenders off balance, he gives Bayern's more explosive forwards like Serge Gnabry and Leroy Sane more room to operate.

With Presnel Kimpembe out, Ramos is now in to provide PSG with more depth and experience. However, the 36-year-old has featured much more frequently than was initially anticipated.

Dayot Upamecano vs. Lionel Messi 

Dayot Upamecano will once more have some work to do on stopping Messi less than two months after the World Cup final, provided he plays, as Galtier thinks he will.

Seven-time Awarded Ballon d'Or Messi scored three goals in Doha, assisted on another, and then scored the winning goal in the shootout.

After a hit-and-miss debut campaign in Bavaria, Upamecano has started each of Bayern's league games this season, elevating his stock.

Without Mbappe's lightning-quick speed, PSG's assault isn't the same. However, Messi and Neymar can still cause plenty of issues for a Bayern defence that has recently been strengthened by the has recently grown more robust the addition of Joao Cancelo.

The UEFA Champions League is coming back from a protracted pause owing to the FIFA World Cup in 2022 in Qatar.

PHOTO | COURTESY Kylian Mbappe will miss the Tuesday clash due to an injury as Mesi is a doubt as well

The competition will see the fierce clubs taking down each other on Tuesday 14th night, where the most significant game is between the bitter Paris Saint Germain from France who will face the furious Bayern Munich in the contest with Paris Saint Germain missing many crucial and essential players like Kylian Mbappe and Lionel Messi, who can also be a doubt as a result of an injury.