user: Question: Who was the opponent in the September 20, 2010 match?
Columns: ['Outcome', 'Date', 'Tournament', 'Surface', 'Opponent', 'Score']
Types: ['text', 'text', 'text', 'text', 'text', 'text']
Sample row: ['Runner-up', 'August 20, 2007', 'Karshi', 'Hard', 'Denis Istomin', '1–6, 4–6']
SQL:

assistant: SELECT "Opponent" FROM "Table" WHERE "Date" = 'September 20, 2010';