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:
| Date | Tournament | Surface | Opponen | Score |
| --- | --- | --- | --- | --- |
| July 18, 2005 | Tarzana , USA | Hard | Alex Bogomolov, Jr. | 6–3, 6–2 |
| January 2, 2006 | São Paulo , Brazil | Hard | Flávio Saretta | 7–6 (7–2) , 6–3 |
| September 25, 2006 | Gramado , Brazil | Hard | Franco Ferreiro | 3–6, 7–6 (7–4) , 6–5 ret. |
| August 4, 2008 | Segovia , Spain | Hard | Sergiy Stakhovsky | 7–5, 7–6 (7–4) |
| September 29, 2008 | Aracaju , Brazil | Clay | Paul Capdeville | 7–5, 6–4 |
| September 16, 2012 | Cali , Colombia | Clay | João Souza | 6–2, 6–4 |
Question:
Which tournament happened on september 25, 2006?
Answer:
Gramado , Brazil