Over the weekend I've played several great 3v3 custom games.  I was Regulus and I believe my team was Rook and Torch Bearer.

Anyway, it was a very back and forth game, think took 45 minutes total.  On Cataract map.

The other team really pushed in and had attacked the Cit a few times.  They had Cats.  There was a lot of defense of the Cit and we leveled up a lot actually.  My maxed out mines alone would wipe out dozens but more came.  So at one point the guys held down the fort while I went deep to the other base to try and capture their portals to stop the wave.  I think the other team was so into taking the Cit down they didn't see me.  I got both portals capped which stopped the waves coming in.  I ported back to base and thought it was too late.  Our 52K Cit was down to 3K pts but the waves cleared and the DGs were killed or backed off (and got their portals back eventually).  Holy cow, 3K!!  But it stood.

Talk about pausing for a breath.  Between the 3 of us we had a ton of gold from all that assult.  We immediately bought up to Giants and starting our own push.  Probably another 10 minutes at least and we made it into their base and eventually won the game.  I think our own Cit had only healed back to 25K or so.

Then another game yesterday only about 10 minutes in and the other team had taken down a few of our forward towers already.  Had people already saying the game was over.  I said no way to my allies and quickly said the above and the comeback.  And we did win that game.

So the point of this post is to just say I don't think any game is really over until that Cit actually comes down.  Don't give up!