Between them, these two clubs have won ten of the last 14 La Liga titles so, come May, will either be able to dethrone Real Madrid?
Barcelona start the weekend at the summit, seeking their first title in four seasons, despite only managing a draw on New Year’s Eve.
Marcos Alonso broke the deadlock at Camp Nou in the Catalan derby, before giving away a daft penalty which helped Espanyol leave with a point.
Before this, Xavi’s team had enjoyed five successive victories in the league, their sole defeat all season coming in el Clásico in mid-October.
Atlético Madrid’s first period of the season was boarder-line catastrophic, finishing last in their Champions League group and suffering league defeats to Cádiz and Mallorca.
Despite that, Diego Simeone’s side returned to action with a victory, albeit against the side rock bottom of the division Elche.
João Félix and then Álvaro Morata on target as los Colchoneros remain fourth, 11 points adrift the leaders.
Both clubs came through tough-looking Copa del Rey ties on Wednesday night to reach the round of 16.
Marcos Llorente and teenaged wonder-kid Pablo Barrios were on target as Atleti edged out Real Oviedo at Estadio Carlos Tartiere.
Meanwhile, in Alicante, Barcelona were involved in an unexpected seven-goal thriller against third-tier opposition.
Despite leading three times, Ronald Araújo, Ousmane Dembélé and Raphinha on target, Barça were taken to extra time by CF Intercity before, eventually, Ansu Fati’s goal saw them advance.
So, can Atlético Madrid claim a statement victory at Cívitas Metropolitano, or will Barcelona return to the top of the table?
Atlético Madrid team news
Highly-rated 19 year old midfielder Pablo Barrios made his full-La Liga debut against Elche, but isn’t expected to be in the starting XI for this one.
At the back, Mario Hermoso’s needless red card in that game means he’ll miss this one through suspension.
So, assuming Diego Simeone sticks with a back five, Reinildo is likely to come in alongside Stefan Savić and José María Giménez.
Yannick Carrasco will continue at left-wing-back; he scored the only goal when Atleti beat Barça during the title winning season.
João Félix wasn’t in the match-day squad in mid-week, fuelling speculation he may leave, but Antoine Griezmann will start, seeking a seventh goal against his former employers.
Predicted XI (5-3-2): Oblak; Molina, Savić, Giménez, Reinildo, Carrasco; Kondogbia, Koke, Llorente; Griezmann, Morata.
Barcelona team news
The big news for Barça is that Robert Lewandowski will miss this game as he starts his three-game ban.
The Polish striker, controversially, started the derby on New Year’s Eve, but the Court of Arbitration for Sport have since upheld his suspension, meaning he won’t be seeing any league action until February.
So, who will lead the line?
It was Memphis in the Copa del Rey on Wednesday, but Xavi might go with Ferran Torres.
At left-back, after Jordi Alba was sent off last weekend, Alejandro Balde will deputise in this huge game
Right-back remains a problem position, it has been for about seven years in truth, so Jules Koundé will continue to fill-in there.
Frenkie de Jong enjoyed a rare start as the pivot against Espanyol, but captain Sergio Busquets will return here.
Predicted XI (4-3-3): ter Stegen; Koundé, Araújo, Christensen, Balde; Busquets, Pedri, Gavi; Dembélé, Raphinha, Torres.