The last game between Atletico Madrid and Barcelona was effectively LaLiga's 2017-18 decider, with Lionel Messi's free-kick sending the Catalans on track to win the title.
Since that March meeting both teams have invested in reinforcements to add depth to their squads, while Andres Iniesta and Gabi are among the key players for the respective teams to have moved on to new clubs.
But Ernesto Valverde and Diego Simeone are set to name very similar sides to that March game when they face off at the Wanda Metropolitano, with Barca having a one-point lead at the top of the table.
Valverde has been criticised for not using his new signings enough and Simeone seems to prefer his trusted old guard. Starting with the five new faces at Atletico, we assess each of the new arrivals to see what impact they have made after switching clubs.
The departure of Sime Vrsaljko to Inter created a spot at right-back, but former PSV defender Arias is yet to nail down the place for himself. He has made five LaLiga appearances this season with Simeone appearing to prefer the experience of Juanfran.
Vrsaljko's fellow Croatia international Kalinic has also been unable to force his way into Simeone's plans, with Antoine Griezmann and Diego Costa a partnership he has not broken. He is yet to score or record an assist from eight appearances in LaLiga and the Champions League.
Atletico paid a reported €60million to sign Lemar from Monaco, but the France international has only scored twice in the league so far. The 23-year-old won the Ligue 1 title at his old club, though, so should improve given time to build relationships with his new team-mates.
Another winger addition, Atletico are yet to reach an agreement with Gelson's old club Sporting CP on his transfer fee. The Portugal international has only played 28 minutes in the Champions League so far and is not typically in Simeone's side for LaLiga matches either.
While his fellow new arrivals are yet to make a real impact, Rodrigo has slotted in seamlessly to Atletico's midfield since returning to the club from Villarreal. The Spain international has made 13 appearances in LaLiga and the Champions League, helping to address the loss of club captain Gabi. Of players to have made at least 500 passes in the league this season, only Fran Beltran and Toni Kroos can better his passing accuracy of 91.83 per cent, while his 36 recoveries is among the best return in the Champions League. At just 22, he should get even better too.
The Brazil midfielder may not welcome the comparisons to Xavi and Iniesta, but Arthur has been such a strong addition to the Barcelona midfield it is easy to see why some onlookers feel he is their successor. Arthur has featured in all four Champions League games since he signed from Gremio, with a particularly dominant performance in their Wembley win over Tottenham. Like Rodrigo, Arthur is just 22 so should be a lynchpin for his new club for many years to come.
Samuel Umtiti's injury has resulted in Lenglet playing perhaps more than Valverde would have planned, the defender starting six LaLiga games so far. He scored an own goal against former club Sevilla, but Barca still ran out 4-2 winners at Camp Nou. "We are delighted by his performance and we are convinced he can do more," said Valverde of Lenglet's start.
Unlike his fellow Brazilian Arthur, Malcom has yet to break into the Barca team on a regular basis. He has played only 82 minutes in LaLiga and made a single brief cameo in the Champions League, although he did score against Inter in that game to open his competitive account for the club.
Vidal has always been a spiky character and he has not changed since joining Barca, earning a public rebuke from general manager Pep Segura for "disrespecting" his team-mates by complaining about a lack of game time. Vidal has recorded two goals and two assists in nine LaLiga appearances, but does not seem to be in Valverde's preferred lineup when he has a full squad available.