Atletico made a strong to their 2021-22 La Liga title defence, winning four and drawing two of their first six matches, but they have dropped down into fourth spot in the table courtesy of last weekend's shock defeat at Alaves, who had lost every league game this season ahead of the clash with the capital giants.
Diego Simeone's side are only three points behind division leaders Real Madrid, though, and as mentioned, will enter this match off the back of an impressive Champions League win, having come from behind to beat Italian giants AC Milan at San Siro on Tuesday night.
Milan took the lead in the 20th minute of the contest through Rafael Leao, but Antoine Griezmann levelled the scores in the 84th minute before Luis Suarez came up with a spectacular 97th-minute winner for the visitors.
Atletico will now be looking to return to winning ways in Spain's top flight and pile the pressure on Koeman, who is expected to remain in charge for Saturday's clash at Wanda Metropolitano, although the Dutchman will not actually be on the bench, as he is serving the second of a two-game touchline suspension.
The Red and Whites recorded a 1-0 win over Barcelona when the two teams met in Madrid last season, and the capital giants are actually unbeaten in their last three La Liga contests with Saturday's opponents, having picked up a point in a goalless draw when they last met at Camp Nou in May.
Barring any surprises, there will not be a change of manager at Barcelona ahead of this match, but it seems unlikely that Koeman will keep his job for much longer unless there is a huge turnaround in form.
Barcelona have not been at their best in La Liga this season, but it has not been a disastrous start, as they are still unbeaten across six matches, recording three wins and three draws to collect 12 points, which has left them in sixth position in the table, five points off leaders Real Madrid with a game in hand.
Indeed, a win on Saturday makes the picture a lot prettier for the Catalan giants, but they are bottom of their Champions League group, having lost their opening two fixtures 3-0 to Bayern Munich and Benfica.
The Catalan giants recorded a 3-0 win over Levante in the league last time out, but they have struggled to draws with Granada and Cadiz in recent weeks, and there is no question that it has been difficult for the team to find their rhythm after a tough summer, largely due to their financial problems.
Whether Koeman is still in charge for the clash with Valencia on October 17 remains to be seen, but Barcelona, despite their issues, have the players to go and win at Wanda Metropolitano, and it will be fascinating to see what occurs in the Spanish capital on Saturday night.