In what is expected to be the most combative match of the weekend in the Spanish league, players are already trading barbs.
Valencia goalkeeper Diego Alves set the tone by questioning Atletico Madrid's physical style of play, and Jorge "Koke" Resurreccion responded that he and his teammates were used to such criticism and were only focused on winning.
The teams will be playing for second place and a possible shot at the league lead.
Also, Barcelona visits Rayo Vallecano looking to bounce back from its 3-2 loss at Paris Saint-Germain, and Real Madrid hosts a slumping Athletic Bilbao.
Here are some things to should know about this week's Spanish league's matches:
WAR OF WORDS
Chances are it won't be the prettiest of matches, but Atletico Madrid's visit to Valencia could be the round's most prickly, if not hot-tempered, contest.
"(Atletico) is a team that competes with you physically, they test the limits of the referees," Valencia goalkeeper Diego Alves said. "We have to match them in this. We can have a good game if we do that. It's an important game against the defending champion. They are favorites but we can be strong at home."
Koke just wants to concentrate on football.
"Well, everyone says we are violent," Koke said. "We just try to focus on playing our style of football, which is to go out on the pitch and get the win. We aren't concerned with what the rest say."
Valencia enters the round ahead of Atletico on goal difference in second place, two points behind Barcelona. Both are unbeaten this season in the league and Atletico will be encouraged, and also worn down, by its 1-0 win over Juventus in the Champions League on Wednesday.
AGAIN THE DEFENSE
Scoring has not been a problem for Barcelona. That's why coach Luis Enrique put his emphasis on shoring up a defense that the club reinforced with its first group of offseason signings in years.
Barcelona started the season in superb fashion by scoring 18 goals while not conceding one through seven straight wins.
But while Lionel Messi and Neymar did their part by scoring goals against PSG on Tuesday, Barcelona's defense allowed its first goals of the season and dug a hole that not even the two South American stars could help it escape.
"Losses always make you worry," Barcelona defender Javier Mascherano said. "We need to correct our mistakes and keep improving."
Rayo's main threat is forward Leo Baptistao, who is enjoying his return on loan from Atletico to the club where he broke out two seasons ago. The Brazilian has scored two goals in each of Rayo's last two wins.
Cristiano Ronaldo has scored 14 goals in 10 appearances this season, and his 10 goals lead the league. But the forward finished Wednesday's match favoring his left leg.
The club hasn't said if he is injured.
Madrid has struggled without Ronaldo this season, losing the Spanish Super Cup to Atletico when Ronaldo wasn't fully fit and falling 4-2 at Real Sociedad when he missed the game because of injury.
This was supposed to be the season when Bilbao consolidated its position as one of Spain's best teams after a fourth-place finish earned the club its first Champions League berth in 16 seasons.
Instead, Bilbao has slumped since eliminating Napoli in the playoffs to reach the group stage of the Champions League, winning only one game of its other eight games.
Bilbao hasn't won at the Santiago Bernabeu since 2005.
CELTA ON RISE
Celta Vigo has found life after the exit of coach Luis Enrique and is flourishing under replacement Eduardo Berizzo.
Led by forward Manuel "Nolito" Agudo's four goals, it is one of four undefeated teams left in the league and has won its last two games.
Celta has refined the passing attack installed by Luis Enrique and Berizzo, a former Celta defender, has made it more reliable at the back.
Celta is in sixth place, level on points with Madrid, and hosts seventh-place Villarreal on Sunday.