Combos mean points, and points mean Gamebreakers - a slow motion race against the clock where goals count double (since they take -1 off your opponent). It's even possible to win a game instantly if you dribble around three players before scoring. No, we're not joking.
And that's the problem - FIFA Street 2 has little to do with football. Getting yourself in a good position to score (ie. one-on-one with the keeper and aiming for the bottom corner) sometimes works, but doing loads of tricks, and thrashing an improbable shot from an acute angle is often as effective, and loose ball first-time shots are almost impossible.
Passing the ball around builds combos, but there's little advantage in 'unlocking' teams, since the tricks are so powerful, you can beat anyone, from anywhere. There are hundreds of tricks (using combos of L2/R2 with right analogue directions) but each is equally powerful, save the occasionally self-defeating overhead flicks.
Winning boils down to crude timing (ie. don't ball juggle into an opponent, or pass to their feet), and raw statistics. A powerful player will almost always win a tackle, however poorly timed, against a weaker player, while a powerful shooter can score from almost anywhere.
Some matches aren't about goals, but points, so the challenge is knowing which buttons you haven't pressed to vary your combo, rather than football. Still, few games let you dress Wayne Rooney in a pink jacket and show his 'mad skillz' to the Scottish street team, or provide such a cheesy ballet of slick passing moves and blistering shots.