Please read the following table in Markdown format and then answer the question according to the table. Table cells in one row are seperated by '|', and different rows are seperated by '
'.

Table:
| Outcome | Year | Championship | Surface | Partner | Opponents in the final | Score in the final |
| --- | --- | --- | --- | --- | --- | --- |
| Winner | 1999.0 | French Open | Clay | Piet Norval | Larisa Neiland Rick Leach | 6–3, 3–6, 6–3 |
| Runner-up | 2002.0 | US Open | Hard | Bob Bryan | Lisa Raymond Mike Bryan | 6–7, 6–7 |
| Winner | 2003.0 | US Open | Hard | Bob Bryan | Lina Krasnoroutskaya Daniel Nestor | 5–7, 7–5, 7–6 (7–5) |
| Runner-up | 2005.0 | US Open | Hard | Nenad Zimonjić | Daniela Hantuchová Mahesh Bhupathi | 4–6, 2–6 |
| Winner | 2006.0 | French Open (2) | Clay | Nenad Zimonjić | Elena Likhovtseva Daniel Nestor | 6–3, 6–4 |
| Runner-up | 2007.0 | French Open | Clay | Nenad Zimonjić | Nathalie Dechy Andy Ram | 5–7, 3–6 |
| Runner-up | 2008.0 | French Open | Clay | Nenad Zimonjić | Victoria Azarenka Bob Bryan | 2–6, 6–7 (4–7) |
| Runner-up | 2008.0 | Wimbledon | Grass | Mike Bryan | Samantha Stosur Bob Bryan | 5–7, 4–6 |
| Winner | 2010.0 | French Open (3) | Clay | Nenad Zimonjić | Yaroslava Shvedova Julian Knowle | 4–6, 7–6 (7–5) , [11–9] |
| Winner | 2011.0 | Australian Open | Hard | Daniel Nestor | Yung-Jan Chan Paul Hanley | 6–3, 3–6, [10–7] |
| Runner-up | 2011.0 | French Open | Clay | Nenad Zimonjić | Casey Dellacqua Scott Lipsky | 6–7 (6–8) , 6–4, [7–10] |
Question:
What was the surface played on when they were a runner-up in 2007?
Answer:
Clay