Ridge Racer

Note: This type of event is similar to the spot races, except you're just racing a ghost car. You have to beat 50 and not just play 50 ghost events.

Self explanatory, simply beat 50 ghosts (Default ghost counts). Ghost battle events are found in the World Race menu, on the left. To check your progress, go to the Statistics area in the Main Menu. The trophy will unlock after beating your 50th race and returning to the Main Menu. You can just keep beating the default ghost if you wish.