So, after routing the Rebels, weakening them and forcing them into a retreat, it's in some way inferior or compensating for failures if the victorious army also cuts off their retreat to finish them off with overwhelming applied offense?
Nothing is known about the battle that happened before this. In fact, there's no indication that a battle even happened before this, apart from some scorch marks on the hull of the Neb-B. As scorch marks don't affect combat readiness and the Rebellion was quite strapped on cash, it's possible they were from a previous engagement entirely. None of the ships were "crippled" in any sense of the word, and the Rebellion forces (except fighters, because Empire) greatly outnumbered the Imperial fleet.
Two Mon Cal frigates, at least two blockade runners, a Neb-B...
The Empire used a probe droid to find a Rebel fleet's location. No indication was given that the Rebels were in retreat, and there's no visible sign that any of the ships present are "crippled" or even damaged. Through tactics and rapid application of firepower,
three two ISDs and an Interdictor took on a vastly superior number of Rebel ships, attacking them between hyperspace jumps. That's the full story that we can see.
So I'm not sure where this allegation of weakness comes from.
EDIT: Whoops. Forgot the Interdictor.