Barcelona host Real Madrid in the first Clasico of the season at Camp Nou, with disputes over Javier Tebas, referees and the Negreira case adding to the buildup.
Mike Maignan was sent off in Milan's Europa League game with Bournemouth on 22 October after shoving Tyler Adams in the face.
Crystal Palace and Besiktas drew 2-2 at Tupras Stadium in the Europa League, leaving Palace on four points and Besiktas unbeaten in Europe.
AGF drew 1-1 with Egnatia in a Conference League home leg on Thursday after Eric Kahl was sent off after two minutes.
FC Copenhagen drew 2-2 away to Crvena Zvezda in the Conference League on Thursday after Bo Svensson rotated his lineup and Maher Carrizo scored the equaliser.
FC Nordsjaelland drew 2-2 with CSKA Sofia in the Conference League after a late equaliser from Leandro Godoy and a red card for Justin Janssen.
Enric Masip, an adviser to Barcelona president Joan Laporta, criticised Real Madrid before Sunday's Clasico over references to the Negreira case.
Viking FK captain Zlatko Tripić said he and his family received troubling messages after he admitted provoking Michael Olise into a red card on 13 October.
