Conversation so far:
What happened with Williams during the Three Tier titles?
Williams then won the Tier I Italian Open in Rome.
Did she play any of the tournaments with her sister?
Williams teamed with Serena to win the women's doubles title at this event, the first Grand Slam title the pair won together.
Where or when did she win her first title?
Williams then successfully defended her titles in both Oklahoma City and Key Biscayne.
Did she loose any matches during this period?
Williams started the 1999 tour in Australia, where she lost to No.
10 Steffi Graf in the quarterfinals of the Medibank International in Sydney.
What other major tournaments did she loose?
She lost her first match at the Bausch & Lomb Championships in Amelia Island, Florida.

Question: What was some of her defeating tournaments?
Self-contained rewrite: What was some of Williams' defeating tournaments?