Costa had denied an English Football Association charge over Saturday’s incident, not seen by referee Mike Dean, in which he appeared to raise his hands to Gunners defender Laurent Koscielny.
But the FA issued a statement Tuesday, saying its “charge against Diego Costa for violent conduct not seen by the match officials but caught on video has been found proven following an Independent Regulatory Commission hearing.
“The Chelsea forward will, therefore, serve the standard penalty of a three-match suspension with immediate effect.”
The decision met with a prompt reaction from Costa’s club.
“We are extremely disappointed with the FA Regulatory Commission’s decision to suspend Diego Costa,” Chelsea said in a statement. “We will await their written reasons before commenting further.”
Earlier on Tuesday, Arsenal defender Gabriel Paulista won an appeal against his red card for confronting Costa after the initial incident during the weekend’s showcase match in the Premier League.
However, Gabriel still faces a separate charge of improper conduct for his reaction after being shown the red card by Dean on the stroke of halftime. The Brazilian failed to immediately leave the pitch and then tried to confront Costa before being restrained by his teammates.
Both clubs still face an outstanding charge of failing to control their players during the ill-tempered match, which Arsenal finished with nine men. Midfielder Santi Cazorla was sent off for the visitors in the second half.