Top Spin 4

Select 'Xbox Live' from the main menu, then 'World Tour'. This is where all the tournaments and other gubbins are located.
All you have to do is select one of the tournaments - 'Quick match' will not work for this as that is only one set - and you will enter the lobby for that event. Once the countdown reaches zero (or sooner in some cases, for example if the lobby is full), you will be matched up with an opponent - if no-one else enters the lobby, then a new one will begin.
All you have to do is win the match without losing a single game. Points are OK to lose, but not a full game. Of course, that's easier said than done, as most people online are quite awesome...
I set up a gaming session to try and get it, as you only need two people to play two matches (obviously the second match will have to be in a different tournament as one of you will have been eliminated form the first one) to each get it - if you are using this method, it is a lot easier to get matched up if you both have female characters, as the vast majority of people play in the male World Tour - so there's more chance of other people entering your lobby, causing you to be matched up with them and not your boosting partner.
As for actual tactics, most people seem to have massive serves and high power ratings, and just hit the ball to either corner to make you run around quite a bit, so if you have good stamina, that's a plus. Also, good drop shots and watching their movement helps, as most people hit from one side then move to the other, so if you hit it to the same side they came from with a power shot, that will wrong-foot them and they will be unable to get a shot off.
But definitely boosting this is waaaaay easier.
Good luck!