One and Done

One and Done is an Achievement in Halo Wars that is unlocked after scoring the winning point in a game of Keepaway against the Legendary AI.

It is worth 30Gamerscore.

Tips
It is recommended to use Professor Anders due to her quick and inexpensive research bonus, on the map Blood River.

This gives a tactical advantage, as you can use your Spartan units and move them to full power to lock down your half of the map.

In the meantime, you can capture the Flag when opportunity comes, as well as increase the power of your army to fend against the enemy.

You should as well use the Arbiter as the Legendary AI. The match may not be too quick, but it will be fairly painless. Using skulls if you have them will help too.