Everton striker Ayegbeni Yakubu has hit back at criticism from former club Middlesbrough by saying: 'I think they have to grow up'.
The Nigerian striker moved to Merseyside from Teesside this summer and Boro chairman Steve Gibson made comments that the forward 'switched off' towards the end of his career at the Riverside Stadium.
Yakubu, though, retorted: 'It is very unfair to say that. I played for Middlesbrough for two years and scored a lot of goals for them, and it is ridiculous for them to say that I switched off.
'I don't have anything against the chairman or the club and so I was very disappointed for him to say things like that.
'But that is his opinion. In the summer, they were saying they did not want to sell me and that they are happy with me. But at the end of the transfer window they decided to sell me and I wanted to leave anyway. I was not happy and I wanted to join a club with more ambition than Middlesbrough.
'They never said I switched off when I left Portsmouth. They all loved me and I would never say anything abusive about Portsmouth.
'So for Middlesbrough to come out and say things like that in the newspaper is not good. You don't do that.
'I think they have to grow up.'