Sevilla, who are 13th, had Coke sent off in the 74th minute in San Sebastian.
Carlos Vela fired Basque club Sociedad ahead in the 18th minute before Gary Medel levelled for the Andalusians four minutes into the second half.
Alberto De La Bella restored the home side’s lead in the 69th minute and defender Coke then picked up two yellow cards in quick succession and was dismissed five minutes later.
Michel was appointed in February to replace the sacked Marcelino and Sevilla, the 2006 and 2007 UEFA Cup winners, ended the season in ninth and failed to qualify for Europe.