I believe its record is 60-0, against mostly or entirely high level pros. It's impressive.
How did an unkown entrant convince high-level pros to take a match? Pros don't like playing random Joes because the chances of an interesting game are vanishingly small.
It was given a "9d" ranking and a "(P)" mark (for "professional") by the Tygem server, who presumably knew its real identity. Also, I get the impression some of the pros did in fact know.