Chelsea manager Jose Mourinho has hit back at former colleague Andre Villas-Boas for revealing that they have fallen out.Villas-Boas also spoke about Mata and believes that Chelsea consider Spurs a dangerous threat to their title ambitions after Mourinho rejected Tottenham's approach for the Spaniard. "I suppose that is a sign of evolution from Tottenham and our ambitions. It is normal. Last year we were fighting for the same objectives in the end so I suppose they wouldn't like to strengthen a rival. The pair will be in opposing dugouts and Villas-Boas is adamant he made the right choice to part company with his mentor. "I don't lose any sleep," said the Spurs boss. "Our break-up point was because I was full of ambition to give him something extra and I wanted further involvement from the job I was doing at that time. "I felt I could give him much more. But he didn't feel the need for somebody near to him or in another position as an assistant, and because of that it was decided that it was time, after Inter Milan, to continue our careers (apart)."