If anyone is interested in obtaining this I will be running it tonight.
GTA Online: Obtain first place in all competitive game types.
There are numerous competitive game types that you must obtain first place in. The complete list is as follows:
Land Race - Standard
Land Race - GTA
Land Race - Rally (either as Driver or Co-Driver).
Arm Wrestling - Minimum one round.
Darts - Minimum 1 leg.
Golf - Minimum 1 hole.
Tennis - Minimum 1 set.
Shooting Range - Win any one of a Cover Target, Random Target or Target Grid match.
Parachuting - Get the highest score and touch the ground first.
Complete a Gang Attack.
Complete all 10 waves of Survival Mode.
Thankfully all of the above can be easily boosted with a single friend or boosting partner in an "Invite Only Session", with the exception of the Rally race and Team Deathmatch which require a minimum of 4 each. Survival Mode and Gang Attack can be done in a Solo Session once you attain Rank 15 and 18 respectively. If boosting, once everyone is in the Private Session you can start any of the race types immediately by pausing, then selecting "Online => Jobs => Host Job => Rockstar Created => Races => *Select Race*". Similarly, you can access Deathmatches by the same method, swapping "Races" in the selection process with "Deathmatches". All other activities must be activated by travelling to their respective icons on the map and hosting that way.
The earliest point at which you can complete this trophy is Rank 18 as that is when Gang Attacks are unlocked. To check which game types you have already won, pause and go to "Stats => Awards => Victory" to see an overview of your medal progress for each specific game type. Not all of the medals in this category denote objectives required to earn this trophy, only those which specifically register the number of wins in the game types listed above.