Diego Simeone's side will enter the match off the back of a 1-1 draw with Real Sociedad in La Liga on Saturday, while Porto were 2-0 winners over Gil Vicente in Primeira Liga last time out.
Match preview
Atletico reached the final of the 2015-16 Champions League before making the semi-finals one year later, but the Red and Whites have found it difficult to make a serious impression in the competition since then.
That said, the capital giants have made the quarter-finals in two of their last three campaigns, including last season, beating Manchester United in the round of 16 before losing to Manchester City in the final eight.
Atletico will play in Group B of this season's tournament alongside Porto, Club Brugge and Bayer Leverkusen, and they will be the favourites to top the section, but it looks to be a very open group, with all four sides surely believing that they can reach the knockout round.
Simeone's side will enter this match off the back of a 1-1 draw with Real Sociedad in La Liga on Saturday, and they are currently in seventh spot in Spain's top flight, boasting seven points from their opening four matches.
The Red and Whites actually faced Porto in the group stage of last season's competition, drawing 0-0 at Wanda Metropolitano before winning 3-1 in the reverse fixture in Portugal.
Atletico lead the head-to-head record between the two sides three victories to two, with Porto's two victories coming in the group stage of the 2009-10 competition.
The Blue and Whites actually made the quarter-finals of the 2020-21 Champions League, but they went out in the groups last term, finishing third behind Liverpool and Atletico, which saw them transfer to the Europa League, where they were eliminated in the round go 16.
Porto, who famously lifted their second European Cup in 2003-04 under Jose Mourinho, won their 30th Portuguese title last term, and they have made a relatively strong start to this season, picking up 12 points from five matches to sit third in the table.
Sergio Conceicao's side were actually beaten 3-1 by Rio Ave in the league at the end of August but will enter this match off the back of a victory, having overcome Gil Vicente on Saturday.
Porto will host Club Brugge in their next European fixture on September 13, and the team's results against the Belgian club and Leverkusen could be crucial when it comes to their chances of making the knockout round.
Atletico Madrid form (all competitions):
Porto form (all competitions):
Team News
Atletico will be missing a number of players for this match, including Felipe through suspension, while Stefan Savic and new arrival Sergio Reguilon are also on the sidelines through injury.
Matheus Cunha and Thomas Lemar also remain doubts, but Nahuel Molina is available after a domestic suspension and should come into the starting side.
Jan Oblak was forced off with a groin problem against Real Sociedad, which could open the door for Ivo Grbic to start, while Alvaro Morata and Joao Felix are set to continue in the final third of the field.
As for Porto, Marko Grujic and Wilson Manafa will miss the match through injury, but the Portuguese champions are otherwise in strong shape heading into the contest.
Head coach Conceicao could make changes from the side that started against Gil Vicente in the league at the weekend, with Evanilson likely to return in the final third of the field.
Joao Mario could also feature at right-back, while Bruno Costa is likely to return in midfield, but David Carmo could drop to the bench for the European contest.
Atletico Madrid possible starting lineup:
Grbic; Gimenez, Witsel, Reinildo; Molina, Llorente, Koke, De Paul, Carrasco; Morata, Felix
Porto possible starting lineup:
D Costa; Mario, Pepe, Marcano, Wendell; Otavio, Uribe, B Costa; Pepe; Evanilson, Taremi
We say: Atletico Madrid 1-1 Porto
Both of these sides will fancy their chances of winning on Wednesday night, but it is very difficult to back Atletico to lose at Wanda Metropolitano in any game against any opposition. It would not be a surprise to see a home victory, but we have a feeling that Porto could pick up a welcome point here.