completely/perfectly by oneself

[keannu]

[FONT=&#48148] Golf is a very fun but hard sport/sports. To play golf, I have to hit such a little/small/tiny ball quite accurately. Usually four people play golf, but play procedure is done completely/perfectly by oneself.[/FONT]

Which is the best option for each underlined?

 

[keannu]

I intended to say "One plays golf totally by oneself even though you play with others". It feels like an individual game as you need to stay focused, and concentrate a lot.
Is the second line better?

Usually four people play golf, but play procedure is done completely/perfectly by oneself.
=> [FONT=바탕]but you play golf [/FONT][FONT=바탕]completely[/FONT][FONT=바탕] by yourself.[/FONT]