user: Question: What was the surface when the opponent was Sergiy Stakhovsky Mikhail Youzhny?
Columns: ['Outcome', 'Date', 'Surface', 'Partner', 'Opponents', 'Score']
Types: ['text', 'text', 'text', 'text', 'text', 'text']
Sample row: ['Runner-up', '26 October 2009', 'Hard (i)', 'Richard Gasquet', 'Colin Fleming Ken Skupski', '6–2, 5–7, [4–10]']
SQL:

assistant: SELECT "Surface" FROM "Table" WHERE "Opponents" = 'Sergiy Stakhovsky Mikhail Youzhny';