NBA 2K11

An even better way of doing this - and a method myself and Mrs Gromzzz discovered during a boosting session y'day - is this:

Get in a party and have both people go into Team Up mode.

Enter the lobby at the same time and start searching for matches. More than likely, due to both people entering the lobby at the same time, you'll find each other.

Now, just wait 45 seconds and hope no-one else joins the lobby. If so, quit and go back in (but this is unlikely to happen if you do it at the right time (which for me, in Melbourne, Australia, was about 9pm).

Now both you and the other person will proceed into a ranked team up game, but you will be on separate teams! This means that when the game is done, the winner will receive recognition for a ranked win!!

Rinse and repeat for all the other online achievements.

NOTE - do not invite your friend into the lobby when in Team Up mode - you'll end up on the same team and the win won't count as a ranked online win.

Simply play and win a online ranked game try and pick a good team. If you're not too good at this game try playing against someone who chooses an average team.