There are 6 maps for Capture the Orb:
Figure of Hate
The game doesn't keep track of which maps you have won a match on, so you might want to write them down on a piece of paper. Winning a match of Capture the Orb is fairly easy, unless you're going against a team that had that one guy who utterly dominates. If you have problems winning on specific maps, take the time to study the maps as each match is 10 minutes long. Figure out strategies for transporting the orb or, if you don't care to get captures, make it really hard for the other team to capture your orb (proximity mines are great for this). After 5 minutes, the orb locations will begin moving to the other side of the map. This can be handy for making captures since you already know where the orb is headed (or, you may end up running into it on the way there).
However, if you manage to join a match in progress and the team you're on wins, it counts towards this achievement. Also, if your team is winning and the people on the other team quit, you will also net a win.