user: Question: Who were the opponents that led to an outcome of Winner on a Grass surface?
Columns: ['Outcome', 'Year', 'Championship', 'Surface', 'Partner', 'Opponents', 'Score']
Types: ['text', 'real', 'text', 'text', 'text', 'text', 'text']
Sample row: ['Winner', 1979.0, 'French Open', 'Clay', 'Bob Hewitt', 'Virginia Ruzici Ion Ţiriac', '6–3, 2–6, 6–3']
SQL:

assistant: SELECT "Opponents" FROM "Table" WHERE "Outcome" = 'Winner' AND "Surface" = 'Grass';