Aston Villa have formally appealed against defender Zat Knight's red card in Boxing Day's feisty 4-4 Premier League draw with Chelsea.

The gangly centre-half was sent off after referee Phil Dowd awarded a penalty against him for a foul on Chelsea midfielder Michael Ballack at Stamford Bridge.

"Villa have officially appealed against Zat Knight's debatable red card at Chelsea," said a statement on Villa's website.

"Martin O'Neill was incensed by the decision and after reviewing the incident again has decided to lodge a formal appeal in the hope that Knight can avoid a ban."