When you hit the #2 position, there will be a message that you're challenging Tiger's place on the leaderboards, so the next tournament will have you paired up with him. This means yes, you have to watch him play too.
Tiger shoots around -10 to -13 per round, so if you've already finished off Tiger Legacy, he's a lot like Rickie Fowler in the final challenge. Set the tournament to one round to make this go by faster.
When you beat him, you don't get the achievement immediately. You have to play the next tournament and maintain your position on the leaderboard for it to unlock.