Each Career is split into 5 tournaments, with progressively harder opponents. As you play through the tournaments you will earn stars, and you need a certain amount to unlock the later tournaments.
For this achievement you do not NEED to complete any of the events on the side of the tournaments, only the matches down the middle. However you may find it easier to unlock extra stars by playing these side events so I would still recommend playing them.
You must complete ALL the matches down the middle to get this achievement. So make sure you have beaten the final of all the tournaments, don't just move onto the next tournament as soon as you have enough stars to unlock it.
In the 5th tournament you will come up against some Master opponents which are pretty tough. Here are a few extra tips which should help beat them:
- Position in 9 ball is particularly important as there will only ever be one ball you're allowed to hit first, so make sure to position the cueball as best as possible by using screw shots and judging the pace of the cueball where appropriate.
- The AI will rarely miss pots so we must try to make life as tricky as possible for them. If you are unable to make a pot on the current ball, make sure to leave the ball in a place which is impossible for the AI to pot too.
- The AI is unable to see plants, so make sure to use this to your advantage. If the 9 ball is near a pocket early on, try to knock another ball into it to win the game quickly.
- The AI doesn't have any safety game at all so if you leave it in a tricky position it will usually open the balls up for you leaving you with an easy pot next time.
These are most of the tips I used to help me beat the career. Please let me know if you have any comments or any other tips you think might be useful too.