Who is the girl that will smith meets in bar after playing pool hitch?

You're likely thinking of the movie Hitch. Will Smith's character, Alex Hitchens, meets Alba, played by Eva Mendes, at a bar after a night of playing pool.

It's worth noting that the specific details about their meeting (like whether he wins or loses the pool game) vary depending on which version of the movie you're watching (theatrical vs. unrated).