Why do team mm games randomly end?

[chemfy]

I was just in a match 2v2 game where my ally died before I had a change to engage and immediately the game ended with a loss.

The game stats on our side were,
my ally 161 loses, 13 kills

I had 0 loses, 6 kills.

This is not the first time this has happened and I was wondering what is the reason for this ?

If one side has twice as many units as the other they automatically win ?

[Major Hemorrhoid's Brother]

Rage quits.

[spicykorean]

I think that if your ally uses the "concede defeat" option to quit, then the game ends for all parties.
If your ally ragequits, then usually the computer AI takes over what remains of his army and the battle continues unless your ally was the designated host of the battle.