http://www.accesstoinsight.org/ptf/dhamma/sacca/sacca4/samma-samadhi/jhana.html
And since there is no such thing called accident, I went deep into the article and it helped me understand the missing point in my meditation -- directing thought and continuous evaluation (which the article calls as evaluation)
Both mind and breath start from the same point, its not possible for the mind to be active when breath is traced to its source and kept there. Breath and mind are very related, controlling one automatically controls the other.