Cheats to win battle with auto resolve?

Barbarian Invasion. Won battle, 100% of enemy dead, about 15% of my troops dead.
Game crashed by the end of it, and I can't be bothered to replay it (cause it'll probably happen again).
When I do auto resolve, I can win, but much of the enemy army survives and escapes to a strategically important city*.
Is there any way to win the battle while killing all of them, as I had done the first time?
Alternatively, is there a command/cheat to destroy all their units?

*in RTW, Auto Resolve always has two possible outcomes - win or defeat. All wins and defeats are always identical, so I can't just save, auto resolve, and load save until I get a desirable result.

I have this situation in the basic RTW game. I suspect that it is due to the algorithm the AI uses to assess casualties. I haven't seenany cheats to cause a wipeout of opponents, although there is one to force a win (in effect fprce the AI to chose between close, clear, and heroic). From ign comes the following

auto_win attacker/defender: Attacker or defender automatically wins the next auto resolved battle.
capture_settlement settlementname: Captures settlement.
kill_character charactername: Kills selected character.

So you could autoresolve and then when the forces retreat into a city you can then force capture of the city (or autoresolve the attack in your favour). That should have the same effect.

PS - never autoresolve if you are facing chariots or have highly prized mercenaries. I have had two units of chariots wipe out 500+ of my attackers when if actually attacking the city yourself you would basically fire-arrow or spear them to destruction.

(If you do face chariots and don't have spearmen/ archers then the best bet is to line your troops up in the form of squares. (9X9) or 11 X 11. The chariots cannot get through them on the charge and then get slaughtered)