Everton boss Roberto Martinez was left angry with ref Lee Mason after defeat to Stoke City.

Martinez hit out at Mason's decisions to only yellow-card Jonathan Walters for pulling back Leighton Baines in the first half and then award a penalty to the visitors moments later, having adjudged James McCarthy to have fouled Bojan Krkic.

Walters had appeared to be the last man in the first incident, while the contact on Bojan, who converted the spot-kick himself, looked minimal in the second.

Mason saw the red card he showed Aston Villa's Gabriel Agbonlahor last Saturday subsequently rescinded this week.

And asked if whether he thought, given the Agbonlahor episode, that Mason should have been allowed to take charge of the Everton-Stoke game, Martinez said: "I don't know, that's not my call - I can only make a call on his performance today, and it was very disappointing.

"It was for everyone to see and maybe the PGMOL (Professional Game Match Officials Limited, the referees' body) need to make a decision about that."

Regarding the penalty decision involving his fellow Spaniard Bojan, Martinez said: "The penalty, I understand it - clearly I know that culture well, that Catalan culture.

"You have been brought up in a way so that you force the referee to make a decision.

"But I don't think there is enough contact for it to be a penalty.

"I can understand why he gave it, but when you look at the replay, both feet go off the ground with no contact and you can understand the striker looking for a decision.

"I can see why he gave it because the two bodies come together - the referee makes a decision.

"But then if he doesn't give the red card, because he is not sure, I don't understand why he gives the penalty - he cannot be sure it is a penalty. So the lack of consistency is what disappoints me."