As the 2020-21 Spanish La Liga resumes this weekend, all eyes will be on the Wanda Metropolitano, where Atletico Madrid welcome Barcelona in a heavyweight clash.
The Rojiblancos are off to a flyer this season, winning five of their opening seven games, and are the only unbeaten side in the division. However, Barcelona have had an indifferent start to the La Liga season, languishing in eighth place with just 11 points in their kitty.
Both sides will miss some key players for their first meeting of the season. Atletico Madrid's Luis Suarez is out after testing positive for COVID-19, and Ansu Fati of Barcelona has suffered a long-term injury.
Nevertheless, there will be plenty to look forward to when Barcelona take on Atletico Madrid at the Wanda Metropolitano. That's because this fixture has produced some really nerve-jangling moments in recent times. On that note, here are the five key players from either team to keep an eye on:
#5 Marc-Andre Ter Stegen (Barcelona)
Barcelona have been very inconsistent in the last two seasons, but one player apart from Lionel Messi who has consistently stepped up for the side is Marc-Andre ter Stegen. The German custodian has bailed his side out on numerous occasions during this period, courtesy his goalkeeping heroics.
Now in his seventh season with Barcelona, the German international missed the first few games of the season due to a knee injury. However, he took little time to conjure his best on his return to action; Ter Stegen pulled off several incredible saves in Barcelona's narrow win at Dynamo Kyiv in the Champions League at the start of the month.
Ronald Koeman will be hoping to see more of the same on Saturday when his side go up against an uncharacteristically menacing Atletico Madrid side that has scored the second-most goals in the 2020-21 La Liga so far.
Ter Stegen conceded twice from the spot in his last meeting against Atletico Madrid. However, he kept a clean sheet on his last visit to the Spanish capital. If he brings his A-game to the fore again, there's no reason to believe that the 28-year old won't pick up another one at the weekend.
#4 Marcos Llorente (Atletico Madrid)
It's hard to believe that Marcos Llorente struggled to break into Real Madrid's first team a few years ago, as he has grown by leaps and bounds since joining Atletico Madrid last summer.
With excellent ball-winning skills, tremendous pace and impressive passing prowess, the 25-year old has become a key component in Diego Simeone's counter-attacking side. Llorente's double against Liverpool back in March is a perfect example in this regard.
Starting mainly on the right side of midfield, Llorente has demonstrated his ability to change the dynamic of a match with his energy and tireless pressing as he bursts forward with real purpose.
In just seven league games this season, Llorente has already equalled his goal tally from the entire 2019-20 campaign, which reflects the star's growing importance to the side. Interestingly, all three of his top-flight goals this season have come at home.
Rest assured, Marcos Llorente could be a huge menace, especially if he manages to cut through the Barcelona defence like he did against Liverpool. If that happens, Atletico Madrid will likely be in the ascendancy.
#3 Antoine Griezmann (Barcelona)
Antonio Griezmann's struggles at Barcelona are apparently showing no signs of abating. The Frenchman has continued to be well below his best for Barcelona, a year on from his gargantuan €120 million transfer from Atletico Madrid.
However, Griezmann has reason for optimism ahead of his return to the Wanda Metropolitano. He has scored in his last two La Liga games this season and would look forward to scoring a league goal against Atletico Madrid for the first time in 11 games.
There might be no better place to continue his new-found momentum than at his old stomping ground. Griezmann, who was on target against his former colleagues in the Super Cup clash this January, will be hoping to get another one against them this weekend.
However, Griezmann will have his task cut out, given Atletico Madrid's formidable recent defensive record; the Rojiblancos have conceded only twice this season, the fewest by any side in the division.
#2 Joao Felix (Atletico Madrid)
Big-money moves don't always come to fruition immediately. In some cases, the player needs time to find his feet in his new surroundings. That has precisely been the case with Joao Felix at Atletico Madrid.
After arriving from Portuguese side Benfica last year on a €126 million transfer, Atletico Madrid's most expensive acquisition and the fourth-most expensive transfer of all time, the 21-year-old didn't quite hit the ground running at the Wanda Metropolitano.
A return of just nine goals from 36 appearances last season left a lot to be desired, but Felix is gradually finding his stride this season, thanks in part to the arrival of Luis Suarez.
With seven goals and three assists in ten games in all competitions this season, Felix is finally starting to justify his hefty price tag and enormous talent. He comes into the Barcelona game on the back of consecutive braces against Osasuna and Cadiz. Felix will fancy his chances of scoring against Barcelona, who haven't been at their best this season.
In the absence of the veteran Uruguayan Suarez, Felix is most likely to start up front as the striker. If that happens, Barcelona's centre-back duo of Gerard Pique and Clement Lenglet will have their hands full.
Barcelona's defence has looked suspect this season; they have conceded eight goals from their opening seven La Liga games. They'll have to muster every ounce of their defensive nous to keep Atletico Madrid and the in-form Felix quiet.
#1 Lionel Messi (Barcelona)
Barcelona captain Lionel Messi has come under fire this season for struggling to score goals from open play, with five of his six strikes in all competitions coming from the penalty spot.
The Argentine ace got the monkey off his back with a superb individual goal against Real Betis in Barcelona's 5-2 thumping right before the international break. He will hope to continue in the same vein against Atletico Madrid.
The Rojiblancos have been one of Messi's favourite punching bags over the years; Messi has scored 32 times against Atletico Madrid in his career, the most he's ever scored against any opponent except Sevilla (37).
There's something about Atletico Madrid that spurs Messi on every time. Even if he doesn't score from open play on Saturday, his playmaking skills could help him conjure opportunities aplenty for his Barcelona colleagues.
Messi has been dropping really deep in recent times, trying to win back possession and pushing his side forward with incisive passes and through balls. If Koke or Saul Niguez don't keep him in check, which would be no mean feat to begin with, the 33-year-old could wreak havoc against Atletico Madrid yet again.