We have to see it in a much more broader picture. We need to realize the sensitivity of the situation, like in contrast to Prophet’s prayer, Abu-Jahal was himself praying to ALLAH to decide in this battle who is right and who is wrong, once and for all. Even they (Mushrikeen) knew the significance of this battle because this was going to be the first battle between Muslims and Mushrikeen. Had Muslims lost this battle, then the whole argument of prophethood would’ve come to an end. We also need to see it from the perspective of Muslims of that time, only 313 of them, with minimal resources–this is the high time for the Prophet to ask ALLAH for his help, both for encouragement of the Muslims and also Dua is in itself a form of Ibadah; who better than Prophet to pray to ALLAH for help and present a role model for us Muslims as well.
So considering the sensitivity of the situation at that time, we must agree that all of Prophet’s actions were completely natural and are actually required of anyone who truly believes in ALLAH.