Tempers fray in frenetic Villarreal farce
Villarreal were leading 2-1 when defender Javi Venta brought down Bilbao's teenage substitute Iker Muniain and conceded a penalty but Diego Lopez palmed away Andoni Iraola's 89th minute spot-kick.
Tempers began to fray and Villarreal defender Diego Godin (pictured) clashed with Bilbao midfielder Javi Martinez and the pair were shown straight red cards.
As he left the pitch Uruguayan Godin had a heated exchange with Caparros, who had to be restrained by officials and was then also sent off.
There was still time for the referee, who played seven minutes of added time, to dismiss Bilbao's Pablo Orbaiz for pulling a prostrate opponent's hair.
The incidents spoiled what had been an entertaining match, with Igor Gabilondo's superb strike levelling for the visitors after Spain defender Joan Capdevila's early opener and Brazilian striker Nilmar scoring the winner just before half-time.
"My sending off was fair because I left my technical area," Caparros said at a news conference.
"But you have to look at the incident that triggered it, the dismissal of Javi Martinez and whether or not he was the victim of an aggression."