The two above methods have been patched.
You still get it in customs with 1 controller - Load up CTF, go to settings and set score to win as "1." Pick a map (I went 1-8 in order), start match, capture flag and repeat 8 times (different maps)
EDIT: As stated by "sTk I" & few others - Quicker work around would be to use the Race Game - with Flag Rally as the type and laps set to 1. Takes less than a minute for every map as stated. Only one point is needed to win the match.
"Saturno" Mentioned that quitting the game worked for them in the Race Game Type. This is not something I tested or can test at this point.
Note: Select "End Game" not "Quit"
"Untalmr" Mentioned it is doable on PC version using the quit out method.