I'm convinced this is entirely luck based. I've played for 12.9 hours and only tied a single game vs. the Easy or Medium A.I (on my second Steam account) and still have no idea how it happened. I haven't been able to replicate it on my main account, despite 5 additional hours of playtime.
The only advice I can give you is either try to force it via. the beginner A.I., or play enough games against the Easy A.I. that you get it by sheer luck.