Virtua Fighter 5 Final Showdown

To earn the achievement "Challenger", you must play at least ten ranked matches.

To find this mode, go to the main menu, then select Xbox LIVE BATTLE, then when the next screen pops up on the screen, select Ranked Match.

Select your character, then play against ten fighters. It can be anybody on XBox Live, whether you fought them before or you haven't fought them before. It also doesn't matter if you win or lose; as long as you play the entire match from start to finish, win or lose, it will count. From your first match, play the next nine matches normally. Once you win or lose the tenth ranked match, the achievement unlocks for good!

If you're having trouble finding opponents to take on in Ranked mode, just switch the settings to "Worldwide" and you should be hooked up with no opponents all the time in a jiff! Credit for this tip goes to OzzysShadyDisco!

Have fun and good luck!

You can also do this with two consoles on your network. What i did was that I installed a copy of the game on my Xbox one. Used a secondary account to load the game on One, while I played on my main on my 360.

You can get this pretty quick doing this way, without boasting or waiting for other players,

Written as of Oct 2021

As the other solutions have mentioned, this achievement is very difficult to do without boosting as the servers are dead; here are two tips to try to make the boosting easier:

The only search parameter which connected my boosting partner and I was "Same Area" search; we never managed to connect with eachother while searching for "Worldwide". I believe "Same Area" is pretty broad, as my partner was in South US while I was in Canada but we still managed to match with one another. This also means that you may not be able to connect with your boosting partner if they're on another continent.

This matchmaking also uses some sort of skill-based metric so make sure neither yourself nor your boosting partner win twice in a row. I'm not too sure if it's based on Battle Points or Win/Loss ratio, but you won't be able to match with your partner if your skill rank is too different. In case that you've already won/loss twice in a row and can't match with your partner, you may need a third partner/dummy account to lose to the person who lost twice in a row or you can hope that someone is on the server and have the person who won twice in a row lose to the random on the server; this should equalize your ratings, allowing you to continue connecting with your boosting partner. The easiest way is to just trade wins each time and you should be able to unlock this very easy achievement in no time!