Round 4
The Black Dragon attacks the Titan, and the Titan retaliates. In its turn, the Titan finishes off the Black Dragon.
In this scenario, I didn't take morale into account. If the Black Dragon is lucky with its morale, or very lucky with its damage, it will win.

"Who is stronger" and "How to defeat the Black Dragon with a Titan" are still somewhat different questions. ;)

From the perspective of single-hit damage, the Titan is stronger; from a statistical perspective, the Black Dragon will win with a higher probability. Also, you are absolutely right – there is a combat tactic that will allow the Titan to have the opportunity to strike first in the fifth round. This is a 100% victory. The only limitation is that the Titan must survive until the fifth round. Considering that the total damage of the Black Dragon over four attacks will be in the range of 252-312 HP (calculated analogously), the probability of defeating the Titan is 21%. Therefore, if the combat tactic you mentioned is followed, in 79% of cases, the Titan (and, in reality, the player controlling the Tower) will prevail.

Regarding Morale – it cannot be taken into account at all, as in this case, it is a cheating tactic and cannot be used to assess the strength of the opponent. Everyone knows that a Butterfly can easily defeat a Legion of Dwarfs, but not because it is stronger...