First off, even though it says "win and never trail," you can loose points, BUT you CANNOT go below the 40 mark. If you go below the 40 mark, you might as well start the match over. (I didn't really know that at first so I'm throwing it out there.)
I found it really easy to get this achievement on Chasms 1v1 with both you and the A.I. as Forge. The first (recommended) thing you should do is activate the skulls Catch, Sugar Cookies, Pain Train, Bountiful Harvest, and Emperor. Build a Warthog, immediately followed by Supply Pads and a Reactor to get your first few points. After that, upgrade your Warthogs to gunner and rush your enemy while continuing to keep crank out more Warthogs for even more points. With those skulls on, there's a lesser chance your Warthogs will die and therefore you wont loose as many points, if at all. As long as you keep this up, you shouldn't fall below 40, so just keep at 'em and after about 5 minutes the achievement'll be yours.
